Progress in the Development of SERS-Active Substrates Based on Metal-Coated Porous Silicon.

PubMed

Bandarenka, Hanna V; Girel, Kseniya V; Zavatski, Sergey A; Panarin, Andrei; Terekhov, Sergei N

2018-05-21

The present work gives an overview of the developments in surface-enhanced Raman scattering (SERS) with metal-coated porous silicon used as an active substrate. We focused this review on the research referenced to SERS-active materials based on porous silicon, beginning from the patent application in 2002 and enclosing the studies of this year. Porous silicon and metal deposition technologies are discussed. Since the earliest studies, a number of fundamentally different plasmonic nanostructures including metallic dendrites, quasi-ordered arrays of metallic nanoparticles (NPs), and metallic nanovoids have been grown on porous silicon, defined by the morphology of this host material. SERS-active substrates based on porous silicon have been found to combine a high and well-reproducible signal level, storage stability, cost-effective technology and handy use. They make it possible to identify and study many compounds including biomolecules with a detection limit varying from milli- to femtomolar concentrations. The progress reviewed here demonstrates the great prospects for the extensive use of the metal-coated porous silicon for bioanalysis by SERS-spectroscopy.

Tuning Selectivity of CO 2 Hydrogenation Reactions at the Metal/Oxide Interface

DOE PAGES

Kattel, Shyam; Liu, Ping; Chen, Jingguang G.

2017-06-26

The chemical transformation of CO 2 not only mitigates the anthropogenic CO 2 emission into the Earth’s atmosphere but also produces carbon compounds that can be used as precursors for the production of chemicals and fuels. The activation and conversion of CO 2 can be achieved on multifunctional catalytic sites available at the metal/oxide interface by taking advantage of the synergy between the metal nanoparticles and oxide support. In this paper, we look at the recent progress in mechanistic studies of CO 2 hydrogenation to C1 (CO, CH 3OH, and CH 4) compounds on metal/oxide catalysts. On this basis, wemore » are able to provide a better understanding of the complex reaction network, grasp the capability of manipulating structure and combination of metal and oxide at the interface in tuning selectivity, and identify the key descriptors to control the activity and, in particular, the selectivity of catalysts. In conclusion, we also discuss challenges and future research opportunities for tuning the selective conversion of CO 2 on metal/oxide catalysts.« less

Heterogeneous Catalysis of Polyoxometalate Based Organic–Inorganic Hybrids

PubMed Central

Ren, Yuanhang; Wang, Meiyin; Chen, Xueying; Yue, Bin; He, Heyong

2015-01-01

Organic–inorganic hybrid polyoxometalate (POM) compounds are a subset of materials with unique structures and physical/chemical properties. The combination of metal-organic coordination complexes with classical POMs not only provides a powerful way to gain multifarious new compounds but also affords a new method to modify and functionalize POMs. In parallel with the many reports on the synthesis and structure of new hybrid POM compounds, the application of these compounds for heterogeneous catalysis has also attracted considerable attention. The hybrid POM compounds show noteworthy catalytic performance in acid, oxidation, and even in asymmetric catalytic reactions. This review summarizes the design and synthesis of organic–inorganic hybrid POM compounds and particularly highlights their recent progress in heterogeneous catalysis. PMID:28788017

Multiheteromacrocycles that Complex Metal Ions. Second Progress Report, 1 May 1975 -- 30 April 1976

DOE R&D Accomplishments Database

Cram, D. J.

1976-01-15

Objective is to develop cyclic and polycyclic host organic compounds to complex and lipophilize metal ions. Macrorings were synthesized: (OCH{sub 2} CH{sub 2} O CH{sub 2}COCH{sub 2} COCH{sub 2}){sub 2} and (OCH{sub 2} CH{sub 2} O CH{sub 2} COCH{sub 2} COCH{sub 2}){sub 3}. The smaller ring complexes divalent metals 10{sup 1+9} times better than the open-chain model CH{sub 3} O CH{sub 2} CO CH{sub 2} COCH{sub 2} O CH{sub 3}, and the order in which metal ions are complexed is Cu{sup 2+}, UO{sub 2}{sup 2+} greater than Ni{sup 2+} greater than Fe{sup 2+}, Co{sup 2+}, Zn{sup 2+}, Cd{sup 2+} greater than Mn{sup 2+}. The UO{sub 2}{sup 2+} and Cu{sup 2+} complexes were isolated and characterized. The larger ring complexes trivalent metals 10{sup 0.9-1.7} times better than the open- chain model compound, and the order is La{sup 3+}, Ce{sup 3+} greater than Cr{sup 3+}. Five other macrocycles were also synthesized, and their binding constants with Na, K, NH{sub 4}, and Cs picrates were measured. Six compounds containing one macroring and two inward-pointing ArOH or ArOCH{sub 3} groups were also prepared and tested for binding of Li, Na, K, Rb, and NH{sub 4} picrates. Racemic compounds containing two binaphthyls and its sulfur analog were prepared. Cage-shaped multiheteromacrocycles containing ten O ligand sites or four S and six O ligand sites were prepared and the binding capability of the first compound for picrates studied. Two ring systems with phosphonate ester groups were also prepared. (DLC)

Preparation of SRN1-type coupling adducts from aliphatic gem-dinitro compounds in ionic liquids.

PubMed

Kamimura, Akio; Toyoshima, Seiichi

2012-04-25

S(RN)1-type coupling adducts are readily prepared by the reaction between a-sulfonylesters or a-cyanosulfones and gem-dinitro compounds in ionic liquids. The reactions progress smoothly and recovered ionic liquids can be used for several iterations, as long as they are washed with water to remove alkali metallic salts. The reaction rate is slower than the corresponding S(RN)1 reaction in DMSO, but no acceleration on irradiation or no inhibition in the presence of m-DNB are observed.

Metallic stents in the management of ureteric strictures

PubMed Central

Kulkarni, Ravi

2014-01-01

Management of ureteric strictures is a challenging task. Subtle presentation, silent progression and complex aetiology may delay diagnosis. A wide range of available treatment options combined with the lack of adequate randomised trials has led to the introduction of personal bias in the management of this difficult group of patients. Metallic ureteric stents offer an alternative to the conventional treatment modalities. A review of the currently available metallic stents and their role in the long-term management of ureteric strictures is presented. Materials used in the manufacture of indwelling urological devices are evolving all the time. Improved endo-urological techniques combined with new devices made from better compounds will continue to improve patient experience. PMID:24497686

Metallic Nickel Nanoparticles May Exhibit Higher Carcinogenic Potential than Fine Particles in JB6 Cells

PubMed Central

Bowman, Linda; Zou, Baobo; Mao, Guochuan; Xu, Jin; Castranova, Vincent; Zhao, Jinshun; Ding, Min

2014-01-01

While numerous studies have described the pathogenic and carcinogenic effects of nickel compounds, little has been done on the biological effects of metallic nickel. Moreover, the carcinogenetic potential of metallic nickel nanoparticles is unknown. Activator protein-1 (AP-1) and nuclear factor-κB (NF-κB) have been shown to play pivotal roles in tumor initiation, promotion, and progression. Mutation of the p53 tumor suppressor gene is considered to be one of the steps leading to the neoplastic state. The present study examines effects of metallic nickel fine and nanoparticles on tumor promoter or suppressor gene expressions as well as on cell transformation in JB6 cells. Our results demonstrate that metallic nickel nanoparticles caused higher activation of AP-1 and NF-κB, and a greater decrease of p53 transcription activity than fine particles. Western blot indicates that metallic nickel nanoparticles induced a higher level of protein expressions for R-Ras, c-myc, C-Jun, p65, and p50 in a time-dependent manner. In addition, both metallic nickel nano- and fine particles increased anchorage-independent colony formation in JB6 P+ cells in the soft agar assay. These results imply that metallic nickel fine and nanoparticles are both carcinogenetic in vitro in JB6 cells. Moreover, metallic nickel nanoparticles may exhibit higher carcinogenic potential, which suggests that precautionary measures should be taken in the use of nickel nanoparticles or its compounds in nanomedicine. PMID:24691273

Platinum, palladium, gold and ruthenium complexes as anticancer agents: Current clinical uses, cytotoxicity studies and future perspectives.

PubMed

Lazarević, Tatjana; Rilak, Ana; Bugarčić, Živadin D

2017-12-15

Metallodrugs offer potential for unique mechanism of drug action based on the choice of the metal, its oxidation state, the types and number of coordinated ligands and the coordination geometry. This review illustrates notable recent progress in the field of medicinal bioinorganic chemistry as many new approaches to the design of innovative metal-based anticancer drugs are emerging. Current research addressing the problems associated with platinum drugs has focused on other metal-based therapeutics that have different modes of action and on prodrug and targeting strategies in an effort to diminish the side-effects of cisplatin chemotherapy. Examples of metal compounds and chelating agents currently in clinical use, clinical trials or preclinical development are highlighted. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Catalytic Arylation and Vinylation Reactions Directed by Anionic Oxygen Functions via Cleavage of C - H and C - C Bonds

NASA Astrophysics Data System (ADS)

Satoh, Tetsuya; Miura, Masahiro

Aromatic compounds having oxygen-containing substituents such as phenols, phenyl ketones, benzyl alcohols, and benzoic acids undergo regioselective arylation and vinylation via C-H bond cleavage in the presence of transition-metal catalysts. The latter two substrates are also arylated and vinylated via C-C bond cleavage accompanied by liberation of ketones and CO2, respectively. Coordination of their anionic oxygen to the metal center is the key to activate the inert bonds effectively and regioselectively. The recent progress of these oxygen-directed reactions is summarized herein.

High-resolution x-ray absorption spectroscopy studies of metal compounds in neurodegenerative brain tissue

NASA Astrophysics Data System (ADS)

Collingwood, J. F.; Mikhaylova, A.; Davidson, M. R.; Batich, C.; Streit, W. J.; Eskin, T.; Terry, J.; Barrea, R.; Underhill, R. S.; Dobson, J.

2005-01-01

Fluorescence mapping and microfocus X-ray absorption spectroscopy are used to detect, locate and identify iron biominerals and other inorganic metal accumulations in neurodegenerative brain tissue at sub-cellular resolution (<5 microns). Recent progress in developing the technique is reviewed. Synchrotron X-rays are used to map tissue sections for metals of interest, and XANES and XAFS are used to characterise anomalous concentrations of the metals in-situ so that they can be correlated with tissue structures and disease pathology. Iron anomalies associated with biogenic magnetite, ferritin and haemoglobin are located and identified in an avian tissue model with a pixel resolution ~5 microns. Subsequent studies include brain tissue sections from transgenic Huntington's mice, and the first high-resolution mapping and identification of iron biominerals in human Alzheimer's and control autopsy brain tissue. Technical developments include use of microfocus diffraction to obtain structural information about biominerals in-situ, and depositing sample location grids by lithography for the location of anomalies by conventional microscopy. The combined techniques provide a breakthrough in the study of both intra- and extra-cellular iron compounds and related metals in tissue. The information to be gained from this approach has implications for future diagnosis and treatment of neurodegeneration, and for our understanding of the mechanisms involved.

Thin films of mixed metal compounds

DOEpatents

Mickelsen, R.A.; Chen, W.S.

1985-06-11

Disclosed is a thin film heterojunction solar cell, said heterojunction comprising a p-type I-III-IV[sub 2] chalcopyrite substrate and an overlying layer of an n-type ternary mixed metal compound wherein said ternary mixed metal compound is applied to said substrate by introducing the vapor of a first metal compound to a vessel containing said substrate from a first vapor source while simultaneously introducing a vapor of a second metal compound from a second vapor source of said vessel, said first and second metals comprising the metal components of said mixed metal compound; independently controlling the vaporization rate of said first and second vapor sources; reducing the mean free path between vapor particles in said vessel, said gas being present in an amount sufficient to induce homogeneity of said vapor mixture; and depositing said mixed metal compound on said substrate in the form of a uniform composition polycrystalline mixed metal compound. 5 figs.

Transition metal catalysis in the generation of petroleum and natural gas. Progress report, [1992--1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mango, F.

1993-08-01

A new hypothesis is introduced for the generation of petroleum and natural gas. The transition metals, activated under the reducing conditions of diagenesis, are proposed as catalysts in the generation of light hydrocarbons. The objective of this proposal is to test that hypothesis. Transition metals (Ni, V, Ti, Co, Fe), in kerogen, porphyrins, and as pure compounds, will be tested under catagenic conditions for catalytic activity in the conversion of normal paraffins and hydrogen into light hydrocarbons. If the hypothesis is correct, kerogenous transition metals should become catalytically active under the reducing conditions of diagenesis and catalyze the conversion ofmore » paraffins into the light hydrocarbons seen in petroleum. Moreover, the C{sub 1}-C{sub 4} hydrocarbons generated catalytically should be similar in molecular and isotopic compositions to natural gas.« less

Bioavailability, Intracellular Mobilization of Nickel, and HIF-1α Activation in Human Lung Epithelial Cells Exposed to Metallic Nickel and Nickel Oxide Nanoparticles

PubMed Central

Liu, Xinyuan; Smith, Ashley; McNeil, Kevin; Weston, Paula; Zhitkovich, Anatoly; Hurt, Robert; Kane, Agnes B.

2011-01-01

Micron-sized particles of poorly soluble nickel compounds, but not metallic nickel, are established human and rodent carcinogens. In contrast, little is known about the toxic effects of a growing number of Ni-containing materials in the nano-sized range. Here, we performed physicochemical characterization of NiO and metallic Ni nanoparticles and examined their metal ion bioavailability and toxicological properties in human lung epithelial cells. Cellular uptake of metallic Ni and NiO nanoparticles, but not metallic Ni microparticles, was associated with the release of Ni(II) ions after 24–48 h as determined by Newport Green fluorescence. Similar to soluble NiCl2, NiO nanoparticles induced stabilization and nuclear translocation of hypoxia-inducible factor 1α (HIF-1α) transcription factor followed by upregulation of its target NRDG1 (Cap43). In contrast to no response to metallic Ni microparticles, nickel nanoparticles caused a rapid and prolonged activation of the HIF-1α pathway that was stronger than that induced by soluble Ni (II). Soluble NiCl2 and NiO nanoparticles were equally toxic to H460 human lung epithelial cells and primary human bronchial epithelial cells; metallic Ni nanoparticles showed lower toxicity and Ni microparticles were nontoxic. Cytotoxicity induced by all forms of Ni occurred concomitant with activation of an apoptotic response, as determined by dose- and time-dependent cleavage of caspases and poly (ADP-ribose) polymerase. Our results show that metallic Ni nanoparticles, in contrast to micron-sized Ni particles, activate a toxicity pathway characteristic of carcinogenic Ni compounds. Moderate cytotoxicity and sustained activation of the HIF-1α pathway by metallic Ni nanoparticles could promote cell transformation and tumor progression. PMID:21828359

Decontamination Systems Information and Research Program. Quarterly technical progress report, January 1--March 31, 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1994-05-01

West Virginia University (WVU) and the US DOE Morgantown Energy Technology Center (METC) entered into a Cooperative Agreement on August 29, 1992 entitled ``Decontamination Systems Information and Research Programs.`` Stipulated within the Agreement is the requirement that WVU submit to METC a series of Technical Progress Reports on a quarterly basis. This report comprises the first Quarterly Technical Progress Report for Year 2 of the Agreement. This report reflects the progress and/or efforts performed on the sixteen (16) technical projects encompassed by the Year 2 Agreement for the period of January 1 through March 31, 1994. In situ bioremediation ofmore » chlorinated organic solvents; Microbial enrichment for enhancing in-situ biodegradation of hazardous organic wastes; Treatment of volatile organic compounds (VOCs) using biofilters; Drain-enhanced soil flushing (DESF) for organic contaminants removal; Chemical destruction of chlorinated organic compounds; Remediation of hazardous sites with steam reforming; Soil decontamination with a packed flotation column; Use of granular activated carbon columns for the simultaneous removal of organics, heavy metals, and radionuclides; Monolayer and multilayer self-assembled polyion films for gas-phase chemical sensors; Compact mercuric iodide detector technology development; Evaluation of IR and mass spectrometric techniques for on-site monitoring of volatile organic compounds; A systematic database of the state of hazardous waste clean-up technologies; Dust control methods for insitu nuclear and hazardous waste handling; Winfield Lock and Dam remediation; and Socio-economic assessment of alternative environmental restoration technologies.« less

Herbal medicine, radical scavenger and metal detoxification: bioinorganic, complexity and nano science perspectives

NASA Astrophysics Data System (ADS)

Sumitro, Sutiman B.; Alit, Sukmaningsih

2018-03-01

Developing Complexity Science and Nano Biological perspective giving the ideas of interfacing between modern physical and biological sciences for more comprehensive understanding of life. The study of bioinorganic is a trans-disciplinary, and will initiate the way to more comprehensive and better understanding life. We can talk about energy generation, motive forces and energy transfer at the level of macromolecules. We can then develop understanding biological behavior on nano size biological materials and its higher order using modern physics as well as thermodynamic law. This is a necessity to ovoid partial understanding of life that are not match with holism. In animal tissues, the accumulation or overwhelmed production of free radicals can damage cells and are believed to accelerate the progression of cancer, cardiovascular disease, and age-related diseases. Thus a guarded balance of radical species is imperative. Edward Kosower [1] proposed an idea of biradical in an aromatic organic compounds. Each of which having unpaired electrons. The magnetic force of this compound used for making agregation based on their magnetic characters. Bioinorganic low molecular weight complex compounds composing herbal medicine can bind toxic metals. This low molecular weight complex molecules then easily excerted the metals from the body, removing them from their either intracellular or extracellular existences. This bioinorganic chelation potential is now inspiring a new therapeutic strategies.

Chemistry of Marine Ligands and Siderophores

PubMed Central

Vraspir, Julia M.; Butler, Alison

2011-01-01

Marine microorganisms are presented with unique challenges to obtain essential metal ions required to survive and thrive in the ocean. The production of organic ligands to complex transition metal ions is one strategy to both facilitate uptake of specific metals, such as iron, and to mitigate the potential toxic effects of other metal ions, such as copper. A number of important trace metal ions are complexed by organic ligands in seawater, including iron, cobalt, nickel, copper, zinc, and cadmium, thus defining the speciation of these metal ions in the ocean. In the case of iron, siderophores have been identified and structurally characterized. Siderophores are low molecular weight iron-binding ligands produced by marine bacteria. Although progress has been made toward the identity of in situ iron-binding ligands, few compounds have been identified that coordinate the other trace metals. Deciphering the chemical structures and production stimuli of naturally produced organic ligands and the organisms they come from is fundamental to understanding metal speciation and bioavailability. The current evidence for marine ligands, with an emphasis on siderophores, and discussion of the importance and implications of metal-binding ligands in controlling metal speciation and cycling within the world’s oceans are presented. PMID:21141029

Aerosol reduction/expansion synthesis (A-RES) for zero valent metal particles

DOEpatents

Leseman, Zayd; Luhrs, Claudia; Phillips, Jonathan; Soliman, Haytham

2016-04-12

Various embodiments provide methods of forming zero valent metal particles using an aerosol-reductive/expansion synthesis (A-RES) process. In one embodiment, an aerosol stream including metal precursor compound(s) and chemical agent(s) that produces reducing gases upon thermal decomposition can be introduced into a heated inert atmosphere of a RES reactor to form zero valent metal particles corresponding to metals used for the metal precursor compound(s).

Superhard composite materials including compounds of carbon and nitrogen deposited on metal and metal nitride carbide and carbonitride

DOEpatents

Wong, M.S.; Li, D.; Chung, Y.W.; Sproul, W.D.; Xi Chu; Barnett, S.A.

1998-03-10

A composite material having high hardness comprises a carbon nitrogen compound, such as CN{sub x} where x is greater than 0.1 and up to 1.33, deposited on a metal or metal compound selected to promote deposition of substantially crystalline CN{sub x}. The carbon nitrogen compound is deposited on a crystal plane of the metal or metal compound sufficiently lattice-matched with a crystal plane of the carbon nitrogen compound that the carbon nitrogen compound is substantially crystalline. A plurality of layers of the compounds can be formed in alternating sequence to provide a multi-layered, superlattice coating having a coating hardness in the range of 45--55 GPa, which corresponds to the hardness of a BN coating and approaches that of a diamond coating. 10 figs.

Superhard composite materials including compounds of carbon and nitrogen deposited on metal and metal nitride, carbide and carbonitride

DOEpatents

Wong, M.S.; Li, D.; Chung, Y.W.; Sproul, W.D.; Chu, X.; Barnett, S.A.

1998-07-07

A composite material having high hardness comprises a carbon nitrogen compound, such as CN{sub x} where x is greater than 0.1 and up to 1.33, deposited on a metal or metal compound selected to promote deposition of substantially crystalline CN{sub x}. The carbon nitrogen compound is deposited on a crystal plane of the metal or metal compound sufficiently lattice-matched with a crystal plane of the carbon nitrogen compound that the carbon nitrogen compound is substantially crystalline. A plurality of layers of the compounds can be formed in alternating sequence to provide a multi-layered, superlattice coating having a coating hardness in the range of 45--55 GPa, which corresponds to the hardness of a BN coating and approaches that of a diamond coating. 10 figs.

Superhard composite materials including compounds of carbon and nitrogen deposited on metal and metal nitride, carbide and carbonitride

DOEpatents

Wong, Ming-Show; Li, Dong; Chung, Yip-Wah; Sproul, William D.; Chu, Xi; Barnett, Scott A.

1998-01-01

A composite material having high hardness comprises a carbon nitrogen compound, such as CN.sub.x where x is greater than 0.1 and up to 1.33, deposited on a metal or metal compound selected to promote deposition of substantially crystalline CN.sub.x. The carbon nitrogen compound is deposited on a crystal plane of the metal or metal compound sufficiently lattice-matched with a crystal plane of the carbon nitrogen compound that the carbon nitrogen compound is substantially crystalline. A plurality of layers of the compounds can be formed in alternating sequence to provide a multi-layered, superlattice coating having a coating hardness in the range of 45-55 GPa, which corresponds to the hardness of a BN coating and approaches that of a diamond coating.

Superhard composite materials including compounds of carbon and nitrogen deposited on metal and metal nitride carbide and carbonitride

DOEpatents

Wong, Ming-Show; Li, Dong; Chung, Yin-Wah; Sproul, William D.; Chu, Xi; Barnett, Scott A.

1998-01-01

A composite material having high hardness comprises a carbon nitrogen compound, such as CN.sub.x where x is greater than 0.1 and up to 1.33, deposited on a metal or metal compound selected to promote deposition of substantially crystalline CN.sub.x. The carbon nitrogen compound is deposited on a crystal plane of the metal or metal compound sufficiently lattice-matched with a crystal plane of the carbon nitrogen compound that the carbon nitrogen compound is substantially crystalline. A plurality of layers of the compounds can be formed in alternating sequence to provide a multi-layered, superlattice coating having a coating hardness in the range of 45-55 GPa, which corresponds to the hardness of a BN coating and approaches that of a diamond coating.

New Approach for Fractioning Metal Compounds Studies in Soils

NASA Astrophysics Data System (ADS)

Minkina, Tatiana; Motuzova, Galina; Mandzhieva, Saglara; Bauer, Tatiana; Burachevskaya, Marina; Sushkova, Svetlana; Nevidomskaya, Dina; Kalinitchenko, Valeriy

2016-04-01

A combined approach for fractioning metal compounds in soils on the basis of sequential (Tessier, 1979) and parallel extractions (1 N NH4Ac, pH 8; 1% EDTA in NH4Ac; and 1N HCl) is proposed. Metal compounds in sequential and parallel extracts are grouped according to the strength of their bonds with soil components. A given group includes metal compounds with similar strengths of bonds and, hence, with similar migration capacities. The groups of firmly and loosely bound metal compounds can be distinguished. This approach has been used to assess the group composition of Zn, Cu, and Pb compounds in an ordinary chernozem and its changes upon the soil contamination with metals. Contamination of an ordinary chernozem from Rostov oblast with heavy metals caused a disturbance of the natural ratios between the metal compounds. In the natural soil, firmly bound metals predominate (88-95%of the total content), which is mainly caused by the fixation of metals in lattices of silicate minerals (56-83%of the total content). The mobility of the metals in the natural soil is low (5-12%) and is mainly related to metal compounds loosely bound with the soil carbonates. Upon the soil contamination with metals (application rates of 100-300 mg/kg), the content of all the metal compounds increases, but the ratio between them shifts towards a higher portion of the potentially mobile metal compounds (up to 30-40% of the bulk contents of the metals). Organic substances and non-silicate Fe, Al, and Mn minerals become the main carriers of the firmly and loosely bound metals. The strengths of their bonds with Cu, Pb, and Zn differ. Lead in the studied chernozems is mainly fixed in a loosely bound form with organic matter, whereas copper and zinc are fixed both by the organic matter and by the non-silicate Fe, Al, and Mn compounds. Firm fixation of the applied Cu and Pb is mainly ensured by the soil organic matter and non-silicate minerals, whereas firm fixation of Zn is mainly due to non-silicate minerals. The amount of the applied metals fixed in the lattices of the silicate minerals is insignificant. Hence, all the soil components participate in the loose and firm fixation of the metals. The leading role in mobilization-immobilization of natural metal compounds in the ordinary chernozem belongs to carbonates and silicate minerals. For exogenic metal compounds, this role belongs to the soil organic matter and Fe-Mn oxides and hydroxides. The obtained data are important for ecology because they enable us to predict the transformation of soil components responsible for metal fixation and the possibility of their secondary mobilization. The danger of metal mobilization is more probable for metal compounds with organic substances that are particularly active in the loose binding of the introduced metals. This work was supported by the Ministry of Science of the Russian Federation, project no. 5.885.2014/K, the Russian Foundation for Basic Research, projects no. № 14-05-00586_a.

Reversible capture of small molecules on bimetallaborane clusters: synthesis, structural characterization, and photophysical aspects.

PubMed

Bould, Jonathan; Baše, Tomáš; Londesborough, Michael G S; Oro, Luis A; Macías, Ramón; Kennedy, John D; Kubát, Pavel; Fuciman, Marcel; Polívka, Tomáš; Lang, Kamil

2011-08-15

Metallaborane compounds containing two adjacent metal atoms, [(PMe(2)Ph)(4)MM'B(10)H(10)] (where MM' = Pt(2), 1; PtPd, 7; Pd(2), 8), have been synthesized, and their propensity to sequester O(2), CO, and SO(2) and to then release them under pulsed and continuous irradiation are described. Only [(PMe(2)Ph)(4)Pt(2)B(10)H(10)], 1, undergoes reversible binding of O(2) to form [(PMe(2)Ph)(4)(O(2))Pt(2)B(10)H(10)] 3, but solutions of 1, 7, and 8 all quantitatively take up CO across their metal-metal vectors to form [(PMe(2)Ph)(4)(CO)Pt(2)B(10)H(10)] 4, [(PMe(2)Ph)(4)(CO)PtPdB(10)H(10)] 10, and [(PMe(2)Ph)(4)(CO)Pd(2)B(10)H(10)] 11, respectively. Crystallographically determined interatomic M-M distances and infrared CO stretching frequencies show that the CO molecule is bound progressively more weakly in the sequence {PtPt} > {PtPd} > {PdPd}. Similarly, SO(2) forms [(PMe(2)Ph)(4)(SO(2))Pt(2)B(10)H(10)] 5, [(PMe(2)Ph)(4)(SO(2))PtPdB(10)H(10)] 12, and [(PMe(2)Ph)(4)(SO(2))Pd(2)B(10)H(10)] 13 with progressively weaker binding of the SO(2) molecule. The uptake and release of gas molecules are accompanied by changes in their absorption spectra. Nanosecond transient absorption spectroscopy clearly shows that the O(2) and CO molecules are liberated from the bimetallic binding site with high quantum yields of about 0.6. For 3, in addition to dioxygen release in the triplet ground state, singlet oxygen O(2)((1)Δ(g)) was also detected with a quantum yield <0.01. In most cases, the release and rebinding of the gas molecules can be cycled with little photodegradation of the compounds. Femtosecond transient absorption spectroscopy further reveals that the photorelease of the O(2) and CO molecules, from 3 and 4 respectively, is an ultrafast process taking place on a time scale of tens of picoseconds. For SO(2), the release is even faster (<1 ps), but only in the case of mixed metal PtPd adducts, most probably because of the metal-metal bonding asymmetry in the mixed metal clusters; for the corresponding symmetric Pt(2) and Pd(2) adducts, 5 and 13, the release of SO(2) is significantly slower (>1 ns). All these compounds may have potential to serve as light-triggered local and instantaneous sources of the studied gases. © 2011 American Chemical Society

Rational design of new materials for spintronics: Co2FeZ (Z=Al, Ga, Si, Ge)

PubMed Central

Balke, Benjamin; Wurmehl, Sabine; Fecher, Gerhard H; Felser, Claudia; Kübler, Jürgen

2008-01-01

Spintronic is a multidisciplinary field and a new research area. New materials must be found for satisfying the different types of demands. The search for stable half-metallic ferromagnets and ferromagnetic semiconductors with Curie temperatures higher than room temperature is still a challenge for solid state scientists. A general understanding of how structures are related to properties is a necessary prerequisite for material design. Computational simulations are an important tool for a rational design of new materials. The new developments in this new field are reported from the point of view of material scientists. The development of magnetic Heusler compounds specifically designed as material for spintronic applications has made tremendous progress in the very recent past. Heusler compounds can be made as half-metals, showing a high spin polarization of the conduction electrons of up to 100% in magnetic tunnel junctions. High Curie temperatures were found in Co2-based Heusler compounds with values up to 1120 K in Co2FeSi. The latest results at the time of writing are a tunnelling magnet resistance (TMR) device made from the Co2FeAl0.5Si0.5 Heusler compound and working at room temperature with a (TMR) effect higher than 200%. Good interfaces and a well-ordered compound are the precondition to realize the predicted half-metallic properties. The series Co2FeAl1- xSix is found to exhibit half-metallic ferromagnetism over a broad range, and it is shown that electron doping stabilizes the gap in the minority states for x=0.5. This might be a reason for the exceptional temperature behaviour of Co2FeAl0.5Si0.5 TMR devices. Using x-ray diffraction (XRD), it was shown conclusively that Co2FeAl crystallizes in the B2 structure whereas Co2FeSi crystallizes in the L21 structure. For the compounds Co2FeGa or Co2FeGe, with Curie temperatures expected higher than 1000 K, the standard XRD technique using laboratory sources cannot be used to easily distinguish between the two structures. For this reason, the EXAFS technique was used to elucidate the structure of these two compounds. Analysis of the data indicated that both compounds crystallize in the L21 structure which makes these two compounds suitable new candidates as materials in magnetic tunnel junctions. PMID:27877928

Thin films of mixed metal compounds

DOEpatents

Mickelsen, Reid A.; Chen, Wen S.

1985-01-01

A compositionally uniform thin film of a mixed metal compound is formed by simultaneously evaporating a first metal compound and a second metal compound from independent sources. The mean free path between the vapor particles is reduced by a gas and the mixed vapors are deposited uniformly. The invention finds particular utility in forming thin film heterojunction solar cells.

Process for forming a metal compound coating on a substrate

DOEpatents

Sharp, D.J.; Vernon, M.E.; Wright, S.A.

1988-06-29

A method of coating a substrate with a thin layer of a metal compound by forming a dispersion of an electrophoretically active organic colloid and a precursor of the metal compound in an electrolytic cell in which the substrate is an electrode. Upon application of an electric potential, the electrode is coated with a mixture of the organic colloid and the precursor to the metal compound, and the coated substrate is then heated in the presence of an atmosphere or vacuum to decompose the organic colloid and form a coating of either a combination of metal compound and carbon, or optionally forming a porous metal compound coating by heating to a temperature high enough to chemically react the carbon.

Reductive precipitation of metals photosensitized by tin and antimony porphyrins

DOEpatents

Shelnutt, John A.; Gong, Weiliang; Abdelouas, Abdesselam; Lutze, Werner

2003-09-30

A method for reducing metals using a tin or antimony porphyrin by forming an aqueous solution of a tin or antimony porphyrin, an electron donor, such as ethylenediaminetetraaceticacid, triethylamine, triethanolamine, and sodium nitrite, and at least one metal compound selected from a uranium-containing compound, a mercury-containing compound, a copper-containing compound, a lead-containing compound, a gold-containing compound, a silver-containing compound, and a platinum-containing compound through irradiating the aqueous solution with light.

Genetic toxicology of thallium: a review.

PubMed

Rodríguez-Mercado, Juan José; Altamirano-Lozano, Mario Agustín

2013-07-01

This review summarizes the current knowledge about the general toxicity of thallium (Tl) and its environmental sources, with special emphasis placed on its potential mutagenic, genotoxic, and cytotoxic effects on both eukaryotic and prokaryotic cells. Tl is a nonessential heavy metal that poses environmental and occupational threats as well as therapeutic hazards because of its use in medicine. It is found in two oxidation states, thallous (Tl(+)) and thallic (Tl(3+)), both of which are considered highly toxic to human beings and domestic and wild organisms. Many Tl compounds are colorless, odorless and tasteless, and these characteristics, combined with the high toxicity of TI compounds, have led to their use as poisons. Because of its similarity to potassium ions (K(+)), plants and mammals readily absorb Tl(+) through the skin and digestive and respiratory systems. In mammals, it can cross the placental, hematoencephalic, and gonadal barriers. Inside cells, Tl can accumulate and interfere with the metabolism of potassium and other metal cations, mimicking or inhibiting their action. The effects of Tl on genetic material have not yet been thoroughly explored, and few existing studies have focused exclusively on Tl(+). Both in vivo and in vitro studies indicate that Tl compounds can have a weak mutagenic effect, but no definitive effect on the induction of primary DNA damage or chromosomal damage has been shown. These studies have demonstrated that Tl compounds are highly toxic and lead to changes in cell-cycle progression.

High-pressure/low-temperature neutron scattering of gas inclusion compounds: Progress and prospects

PubMed Central

Zhao, Yusheng; Xu, Hongwu; Daemen, Luke L.; Lokshin, Konstantin; Tait, Kimberly T.; Mao, Wendy L.; Luo, Junhua; Currier, Robert P.; Hickmott, Donald D.

2007-01-01

Alternative energy resources such as hydrogen and methane gases are becoming increasingly important for the future economy. A major challenge for using hydrogen is to develop suitable materials to store it under a variety of conditions, which requires systematic studies of the structures, stability, and kinetics of various hydrogen-storing compounds. Neutron scattering is particularly useful for these studies. We have developed high-pressure/low-temperature gas/fluid cells in conjunction with neutron diffraction and inelastic neutron scattering instruments allowing in situ and real-time examination of gas uptake/release processes. We studied the formation of methane and hydrogen clathrates, a group of inclusion compounds consisting of frameworks of hydrogen-bonded H2O molecules with gas molecules trapped inside the cages. Our results reveal that clathrate can store up to four hydrogen molecules in each of its large cages with an intermolecular H2–H2 distance of only 2.93 Å. This distance is much shorter than that in the solid/metallic hydrogen (3.78 Å), suggesting a strong densification effect of the clathrate framework on the enclosed hydrogen molecules. The framework-pressurizing effect is striking and may exist in other inclusion compounds such as metal-organic frameworks (MOFs). Owing to the enormous variety and flexibility of their frameworks, inclusion compounds may offer superior properties for storage of hydrogen and/or hydrogen-rich molecules, relative to other types of compounds. We have investigated the hydrogen storage properties of two MOFs, Cu3[Co(CN)6]2 and Cu3(BTC)2 (BTC = benzenetricarboxylate), and our preliminary results demonstrate that the developed neutron-scattering techniques are equally well suited for studying MOFs and other inclusion compounds. PMID:17389387

New concepts for molecular magnets

NASA Astrophysics Data System (ADS)

Pilawa, Bernd

1999-03-01

Miller and Epstein (1994) define molecular magnets as magnetic materials which are prepared by the low-temperature methods of the preparative chemistry. This definition includes molecular crystals of neutral radicals, radical salts and charge transfer complexes as well as metal complexes and polymers with unpaired spins (Dormann 1995). The challenge of molecular magnets consists in tailoring magnetic properties by specific modifications of the molecular units. The combination of magnetism with mechanical or electrical properties of molecular compounds promise materials of high technical interest (Gatteschi 1994a and 1994b, Möhwald 1996) and both the chemical synthesis of new molecular materials with magnetic properties as well as the physical investigation and explanation of these properties is important, in order to achieve any progress. This work deals with the physical characterization of the magnetic properties of molecular materials. It is organized as follows. In the first part molecular crystals of neutral radicals are studied. After briefly discussing the general magnetic properties of these materials and after an overview over the physical principles of exchange interaction between organic radicals I focus on the interplay between the crystallographic structure and the magnetic properties of various derivatives of the verdazyl and nitronyl nitroxide radicals. The magnetic properties of metal complexes are the subject of the second part. After an overview over the experimental and theoretical tools which are used for the investigation of the magnetic properties I shortly discuss the exchange coupling of transition metal ions and the magnetic properties of complexes of two and three metal ions. Special emphasis is given to spin cluster compounds. Spin cluster denote complexes of many magnetic ions. They are attractive as building blocks of molecular magnets as well as magnetic model compounds for the study of spin frustration, molecular super-paramagnetism and quasi one-dimensional magnets.

Orally Active Multi-Functional Antioxidants Delay Cataract Formation in Streptozotocin (Type 1) Diabetic and Gamma-Irradiated Rats

PubMed Central

Randazzo, James; Zhang, Peng; Makita, Jun; Blessing, Karen; Kador, Peter F.

2011-01-01

Background Age-related cataract is a worldwide health care problem whose progression has been linked to oxidative stress and the accumulation of redox-active metals. Since there is no specific animal model for human age-related cataract, multiple animal models must be used to evaluate potential therapies that may delay and/or prevent cataract formation. Methods/Principal Findings Proof of concept studies were conducted to evaluate 4-(5-hydroxypyrimidin-2-yl)-N,N-dimethyl-3,5-dioxopiperazine-1-sulfonamide (compound 4) and 4-(5-hydroxy-4,6-dimethoxypyrimidin-2-yl)-N,N-dimethyl-3,5-dioxopiperazine-1-sulfonamide (compound 8), multi-functional antioxidants that can independently chelate redox metals and quench free radicals, on their ability to delay the progression of diabetic “sugar” cataracts and gamma radiation-induced cataracts. Prior to 15 Gy of whole head irradiation, select groups of Long Evans rats received either diet containing compound 4 or 8, or a single i.p. injection of panthethine, a radioprotective agent. Compared to untreated, irradiated rats, treatment with pantethine, 4 and 8 delayed initial lens changes by 4, 47, and 38 days, respectively, and the average formation of posterior subcapsular opacities by 23, 53 and 58 days, respectively. In the second study, select groups of diabetic Sprague Dawley rats were administered chow containing compounds 4, 8 or the aldose reductase inhibitor AL1576. As anticipated, treatment with AL1576 prevented cataract by inhibiting sorbitol formation in the lens. However, compared to untreated rats, compounds 4 and 8 delayed vacuole formation by 20 days and 12 days, respectively, and cortical cataract formation by 8 and 3 days, respectively, without reducing lenticular sorbitol. Using in vitro lens culture in 30 mM xylose to model diabetic “sugar” cataract formation, western blots confirmed that multi-functional antioxidants reduced endoplasmic reticulum stress. Conclusions/Significance Multi-functional antioxidants delayed cataract formation in two diverse rat models. These studies provide a proof of concept that a general cataract treatment focused on reducing oxidative stress instead of a specific mechanism of cataractogenesis can be developed. PMID:21541328

DEVELOPMENT OF DIES FOR EXTRUSION OF COMPLEX SHAPES OF STEEL AND REFRACTORY ALLOYS. Interim Technical Documentary Progress Report to Aeronautical Systems Division for the Period September 16,1962 through December 31, 1962

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hunt, J.G.; Jenkins, R.G.; White, A.M.

1963-03-01

A number of ceramics, metallic compounds, and ceramic-metal composites were successfully hot pressed into the shape of die inserts. Steels were extruded through several of these for the purpose of evaluating the materials or to study methods of supporting the die inserts. Refractory metal inserts were also used in similar tests. Hot pressed inserts consisting of 80 vo1% Al/sub 2/O/ sub 3/--10 vol% W and 80 vol% ThO/sub 2/--10 vol% W cracked but did not erode. Sintered molybdenum inserts flowed excessively, whereas sintered tungsten inserts flowed to a lesser degree. A hard die casing with a slight shrink fit appearsmore » to be the most satisfactory method of support. (auth)« less

Relaxation dynamics of dysprosium(III) single molecule magnets.

PubMed

Guo, Yun-Nan; Xu, Gong-Feng; Guo, Yang; Tang, Jinkui

2011-10-21

Over the past decade, lanthanide compounds have become of increasing interest in the field of Single Molecule Magnets (SMMs) due to the large inherent anisotropy of the metal ions. Heavy lanthanide metal systems, in particular those containing the dysprosium(III) ion, have been extensively employed to direct the formation of a series of SMMs. Although remarkable progress is being made regarding the synthesis and characterization of lanthanide-based SMMs, the understanding and control of the relaxation dynamics of strongly anisotropic systems represents a formidable challenge, since the dynamic behaviour of lanthanide-based SMMs is significantly more complex than that of transition metal systems. This perspective paper describes illustrative examples of pure dysprosium(III)-based SMMs, published during the past three years, showing new and fascinating phenomena in terms of magnetic relaxation, aiming at shedding light on the features relevant to modulating relaxation dynamics of polynuclear lanthanide SMMs. This journal is © The Royal Society of Chemistry 2011

Metal Phosphides and Phosphates-based Electrodes for Electrochemical Supercapacitors.

PubMed

Li, Xin; Elshahawy, Abdelnaby M; Guan, Cao; Wang, John

2017-10-01

Phosphorus compounds, such as metal phosphides and phosphates have shown excellent performances and great potential in electrochemical energy storage, which are demonstrated by research works published in recent years. Some of these metal phosphides and phosphates and their hybrids compare favorably with transition metal oxides/hydroxides, which have been studied extensively as a class of electrode materials for supercapacitor applications, where they have limitations in terms of electrical and ion conductivity and device stability. To be specific, metal phosphides have both metalloid characteristics and good electric conductivity. For metal phosphates, the open-framework structures with large channels and cavities endow them with good ion conductivity and charge storage capacity. In this review, we present the recent progress on metal phosphides and phosphates, by focusing on their advantages/disadvantages and potential applications as a new class of electrode materials in supercapacitors. The synthesis methods to prepare these metal phosphides/phosphates are looked into, together with the scientific insights involved, as they strongly affect the electrochemical energy storage performance. Particular attentions are paid to those hybrid-type materials, where strong synergistic effects exist. In the summary, the future perspectives and challenges for the metal phosphides, phosphates and hybrid-types are proposed and discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemical vapor deposition of group IIIB metals

DOEpatents

Erbil, A.

1989-11-21

Coatings of Group IIIB metals and compounds thereof are formed by chemical vapor deposition, in which a heat decomposable organometallic compound of the formula given in the patent where M is a Group IIIB metal, such as lanthanum or yttrium and R is a lower alkyl or alkenyl radical containing from 2 to about 6 carbon atoms, with a heated substrate which is above the decomposition temperature of the organometallic compound. The pure metal is obtained when the compound of the formula 1 is the sole heat decomposable compound present and deposition is carried out under nonoxidizing conditions. Intermetallic compounds such as lanthanum telluride can be deposited from a lanthanum compound of formula 1 and a heat decomposable tellurium compound under nonoxidizing conditions.

Chemical vapor deposition of group IIIB metals

DOEpatents

Erbil, Ahmet

1989-01-01

Coatings of Group IIIB metals and compounds thereof are formed by chemical vapor deposition, in which a heat decomposable organometallic compound of the formula (I) ##STR1## where M is a Group IIIB metal, such as lanthanum or yttrium and R is a lower alkyl or alkenyl radical containing from 2 to about 6 carbon atoms, with a heated substrate which is above the decomposition temperature of the organometallic compound. The pure metal is obtained when the compound of the formula I is the sole heat decomposable compound present and deposition is carried out under nonoxidizing conditions. Intermetallic compounds such as lanthanum telluride can be deposited from a lanthanum compound of formula I and a heat decomposable tellurium compound under nonoxidizing conditions.

Rhizofiltration - the use of plants to remove heavy metals from aqueous streams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raskin, I.; Dushenkov, V.; Kumar, P.B.A.N.

1995-12-31

Heavy metal pollution of water is a major environmental problem facing the modern world. Rhizofiltration - the use of plant roots to remove heavy metals from water is an emerging environmental clean-up technology. Roots of many hydroponically grown terrestrial plants e.g. Indian mustard, sunflower (Hefianthus annuus L.) and various grasses effectively removed toxic metals such as CU{sup -2}, Cd{sup +2}Cr{sup +6}, Ni{sup +2}Pb{sup +2} and Zn{sup +2} from aqueous solutions. Roots of B. juncea concentrated these metals 131 to 563-fold (on a DW basis) above initial solution concentrations. Pb removal was based on tissue absorption and on root-mediated Pb precipitationmore » in the form of insoluble inorganic compounds, mainly Pb phosphate. At high Pb concentrations precipitation played a progressively more important role in Pb removal than tissue absorption, which saturated at approximately 100 {mu}g Pb/g DW root. Dried roots were much less effective than live roots in accumulating Pb and in removing Pb from the solution.« less

[Biological activity of selenorganic compounds at heavy metal salts intoxication].

PubMed

Rusetskaya, N Y; Borodulin, V B

2015-01-01

Possible mechanisms of the antitoxic action of organoselenium compounds in heavy metal poisoning have been considered. Heavy metal toxicity associated with intensification of free radical oxidation, suppression of the antioxidant system, damage to macromolecules, mitochondria and the genetic material can cause apoptotic cell death or the development of carcinogenesis. Organic selenium compounds are effective antioxidants during heavy metal poisoning; they exhibit higher bioavailability in mammals than inorganic ones and they are able to activate antioxidant defense, bind heavy metal ions and reactive oxygen species formed during metal-induced oxidative stress. One of promising organoselenium compounds is diacetophenonyl selenide (DAPS-25), which is characterized by antioxidant and antitoxic activity, under conditions including heavy metal intoxication.

First-row transition metal hydrogenation and hydrosilylation catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trovitch, Ryan J.; Mukhopadhyay, Tufan K.; Pal, Raja

Transition metal compounds, and specifically transition metal compounds having a tetradentate and/or pentadentate supporting ligand are described, together with methods for the preparation thereof and the use of such compounds as hydrogenation and/or hydrosilylation catalysts.

Light-induced catalytic and cytotoxic properties of phosphorescent transition metal compounds with a d8 electronic configuration.

PubMed

To, Wai-Pong; Zou, Taotao; Sun, Raymond Wai-Yin; Che, Chi-Ming

2013-07-28

Transition metal compounds are well documented to have diverse applications such as in catalysis, light-emitting materials and therapeutics. In the areas of photocatalysis and photodynamic therapy, metal compounds of heavy transition metals are highly sought after because they can give rise to triplet excited states upon photoexcitation. The long lifetimes (more than 1 μs) of the triplet states of transition metal compounds allow for bimolecular reactions/processes such as energy transfer and/or electron transfer to occur. Reactions of triplet excited states of luminescent metal compounds with oxygen in cells may generate reactive oxygen species and/or induce damage to DNA, leading to cell death. This article recaps the recent findings on photochemical and phototoxic properties of luminescent platinum(II) and gold(III) compounds both from the literature and experimental results from our group.

Tin phosphide-based anodes for sodium-ion batteries: synthesis via solvothermal transformation of Sn metal and phase-dependent Na storage performance

PubMed Central

Shin, Hyun-Seop; Jung, Kyu-Nam; Jo, Yong Nam; Park, Min-Sik; Kim, Hansung; Lee, Jong-Won

2016-01-01

There is a great deal of current interest in the development of rechargeable sodium (Na)-ion batteries (SIBs) for low-cost, large-scale stationary energy storage systems. For the commercial success of this technology, significant progress should be made in developing robust anode (negative electrode) materials with high capacity and long cycle life. Sn-P compounds are considered promising anode materials that have considerable potential to meet the required performance of SIBs, and they have been typically prepared by high-energy mechanical milling. Here, we report Sn-P-based anodes synthesised through solvothermal transformation of Sn metal and their electrochemical Na storage properties. The temperature and time period used for solvothermal treatment play a crucial role in determining the phase, microstructure, and composition of the Sn-P compound and thus its electrochemical performance. The Sn-P compound prepared under an optimised solvothermal condition shows excellent electrochemical performance as an SIB anode, as evidenced by a high reversible capacity of ~560 mAh g−1 at a current density of 100 mA g−1 and cycling stability for 100 cycles. The solvothermal route provides an effective approach to synthesising Sn-P anodes with controlled phases and compositions, thus tailoring their Na storage behaviour. PMID:27189834

Nuclear staining with alum hematoxylin.

PubMed

Llewellyn, B D

2009-08-01

The hematoxylin and eosin stain is the most common method used in anatomic pathology, yet it is a method about which technologists ask numerous questions. Hematoxylin is a natural dye obtained from a tree originally found in Central America, and is easily converted into the dye hematein. This dye forms coordination compounds with mordant metals, such as aluminum, and the resulting lake attaches to cell nuclei. Regressive formulations contain a higher concentration of dye than progressive formulations and may also contain a lower concentration of mordant. The presence of an acid increases the life of the solution and in progressive solutions may also affect selectivity of staining. An appendix lists more than 60 hemalum formulations and the ratio of dye to mordant for each.

Process of forming compounds using reverse micelle or reverse microemulsion systems

DOEpatents

Linehan, John C.; Fulton, John L.; Bean, Roger M.

1998-01-01

The present invention is directed to a process for producing a nanometer-sized metal compound. The process comprises forming a reverse micelle or reverse microemulsion system comprising a polar fluid in a non-polar or low-polarity fluid. A first reactant comprising a multi-component, water-soluble metal compound is introduced into the polar fluid in a non-polar or low-polarity fluid. This first reactant can be introduced into the reverse micelle or reverse microemulsion system during formation thereof or subsequent to the formation of the reverse micelle or microemulsion system. The water-soluble metal compound is then reacted in the reverse micelle or reverse microemulsion system to form the nanometer-sized metal compound. The nanometer-sized metal compound is then precipitated from the reverse micelle or reverse microemulsion system.

Heteronuclear Metal Cluster Compounds Synthesis and Reactivity

DTIC Science & Technology

1990-08-10

important role in the formation of complexes with heteronuclear metal - metal bonds. Since this is our Final Report recent results are reported and...DTe FL’ Copy AFOSR-86-0125 Lfl X’ HETERONUCLEAR METAL CLUSTER COMPOUNDS00 SYNTHESIS AND REACTIVITY F. Gordon A. Stone, IDepartment of Inorganic...Security Classification) HETERONUCLEAR METAL CLUSTER COMPOUNDS: SYNTHESIS AND REACTIVITY 12. PERSONAL AUTHOR(S) F. GORDON A. STONE 13a. TYPE OF REPORT

Method of bonding metals with a radio-opaque adhesive/sealant for void detection and product made

NASA Technical Reports Server (NTRS)

Hermansen, Ralph D. (Inventor); Sutherland, Thomas H. (Inventor); Predmore, Roamer (Inventor)

1990-01-01

A method and structure for providing radio-opaque polymer compounds for use in metal bonding and sealing. A powder filler comprising a high atomic number metal or compound thereof is incorporated into a polymer compound to render it more radio-opaque than the surrounding metal structures. Voids or other discontinuities in the radio-opaque polymer compound can then be detected by x-ray inspection or other non-destructive radiographic procedure.

Doped palladium containing oxidation catalysts

DOEpatents

Mohajeri, Nahid

2014-02-18

A supported oxidation catalyst includes a support having a metal oxide or metal salt, and mixed metal particles thereon. The mixed metal particles include first particles including a palladium compound, and second particles including a precious metal group (PMG) metal or PMG metal compound, wherein the PMG metal is not palladium. The oxidation catalyst may also be used as a gas sensor.

Carbon dioxide capture process with regenerable sorbents

DOEpatents

Pennline, Henry W.; Hoffman, James S.

2002-05-14

A process to remove carbon dioxide from a gas stream using a cross-flow, or a moving-bed reactor. In the reactor the gas contacts an active material that is an alkali-metal compound, such as an alkali-metal carbonate, alkali-metal oxide, or alkali-metal hydroxide; or in the alternative, an alkaline-earth metal compound, such as an alkaline-earth metal carbonate, alkaline-earth metal oxide, or alkaline-earth metal hydroxide. The active material can be used by itself or supported on a substrate of carbon, alumina, silica, titania or aluminosilicate. When the active material is an alkali-metal compound, the carbon-dioxide reacts with the metal compound to generate bicarbonate. When the active material is an alkaline-earth metal, the carbon dioxide reacts with the metal compound to generate carbonate. Spent sorbent containing the bicarbonate or carbonate is moved to a second reactor where it is heated or treated with a reducing agent such as, natural gas, methane, carbon monoxide hydrogen, or a synthesis gas comprising of a combination of carbon monoxide and hydrogen. The heat or reducing agent releases carbon dioxide gas and regenerates the active material for use as the sorbent material in the first reactor. New sorbent may be added to the regenerated sorbent prior to subsequent passes in the carbon dioxide removal reactor.

Metal resistance sequences and transgenic plants

DOEpatents

Meagher, Richard Brian; Summers, Anne O.; Rugh, Clayton L.

1999-10-12

The present invention provides nucleic acid sequences encoding a metal ion resistance protein, which are expressible in plant cells. The metal resistance protein provides for the enzymatic reduction of metal ions including but not limited to divalent Cu, divalent mercury, trivalent gold, divalent cadmium, lead ions and monovalent silver ions. Transgenic plants which express these coding sequences exhibit increased resistance to metal ions in the environment as compared with plants which have not been so genetically modified. Transgenic plants with improved resistance to organometals including alkylmercury compounds, among others, are provided by the further inclusion of plant-expressible organometal lyase coding sequences, as specifically exemplified by the plant-expressible merB coding sequence. Furthermore, these transgenic plants which have been genetically modified to express the metal resistance coding sequences of the present invention can participate in the bioremediation of metal contamination via the enzymatic reduction of metal ions. Transgenic plants resistant to organometals can further mediate remediation of organic metal compounds, for example, alkylmetal compounds including but not limited to methyl mercury, methyl lead compounds, methyl cadmium and methyl arsenic compounds, in the environment by causing the freeing of mercuric or other metal ions and the reduction of the ionic mercury or other metal ions to the less toxic elemental mercury or other metals.

Aerosol chemical vapor deposition of metal oxide films

DOEpatents

Ott, K.C.; Kodas, T.T.

1994-01-11

A process of preparing a film of a multicomponent metal oxide including: forming an aerosol from a solution comprised of a suitable solvent and at least two precursor compounds capable of volatilizing at temperatures lower than the decomposition temperature of said precursor compounds; passing said aerosol in combination with a suitable oxygen-containing carrier gas into a heated zone, said heated zone having a temperature sufficient to evaporate the solvent and volatilize said precursor compounds; and passing said volatilized precursor compounds against the surface of a substrate, said substrate having a sufficient temperature to decompose said volatilized precursor compounds whereby metal atoms contained within said volatilized precursor compounds are deposited as a metal oxide film upon the substrate is disclosed. In addition, a coated article comprising a multicomponent metal oxide film conforming to the surface of a substrate selected from the group consisting of silicon, magnesium oxide, yttrium-stabilized zirconium oxide, sapphire, or lanthanum gallate, said multicomponent metal oxide film characterized as having a substantially uniform thickness upon said substrate.

Compound surface-plasmon-polariton waves guided by a thin metal layer sandwiched between a homogeneous isotropic dielectric material and a structurally chiral material

NASA Astrophysics Data System (ADS)

Chiadini, Francesco; Fiumara, Vincenzo; Scaglione, Antonio; Lakhtakia, Akhlesh

2016-03-01

Multiple compound surface plasmon-polariton (SPP) waves can be guided by a structure consisting of a sufficiently thick layer of metal sandwiched between a homogeneous isotropic dielectric (HID) material and a dielectric structurally chiral material (SCM). The compound SPP waves are strongly bound to both metal/dielectric interfaces when the thickness of the metal layer is comparable to the skin depth but just to one of the two interfaces when the thickness is much larger. The compound SPP waves differ in phase speed, attenuation rate, and field profile, even though all are excitable at the same frequency. Some compound SPP waves are not greatly affected by the choice of the direction of propagation in the transverse plane but others are, depending on metal thickness. For fixed metal thickness, the number of compound SPP waves depends on the relative permittivity of the HID material, which can be useful for sensing applications.

Research and Development on Wear Metal Analysis.

DTIC Science & Technology

1982-01-01

claim by NBS (11) that these compounds are mostly oils and more difficult to isolate and purify than other metal carboxylates . a. Experimental (1...acetates are inexpensive and readily available organometallic compounds. Since other metal carboxylates such as metal 2-ethylhexanoates and metal caprates

Valence-Bond Concepts in Coordination Chemistry and the Nature of Metal-Metal Bonds.

ERIC Educational Resources Information Center

Pauling, Linus; Herman, Zelek S.

1984-01-01

Discusses the valence-bond method, applying it to some coordination compounds of metals, especially those involving metal-metal bonds. Suggests that transition metals can form as many as nine covalent bonds, permitting valence-theory to be extended to transition metal compounds in a more effective way than has been possible before. (JN)

Some issues for blast from a structural reactive material solid

NASA Astrophysics Data System (ADS)

Zhang, F.

2018-07-01

Structural reactive material (SRM) is consolidated from a mixture of micro- or nanometric reactive metals and metal compounds to the mixture theoretical maximum density. An SRM can thus possess a higher energy density, relying on various exothermic reactions, and higher mechanical strength and heat resistance than that of conventional CHNO explosives. Progress in SRM solid studies is reviewed specifically as an energy source for air blast through the reaction of fine SRM fragments under explosive loading. This includes a baseline SRM solid explosion characterization, material properties of an SRM solid, and its dynamic fine fragmentation mechanisms and fragment reaction mechanisms. The overview is portrayed mainly from the author's own experimental studies combined with theoretical and numerical explanation. These advances have laid down some fundamentals for the next stage of developments.

Some issues for blast from a structural reactive material solid

NASA Astrophysics Data System (ADS)

Zhang, F.

2018-03-01

Structural reactive material (SRM) is consolidated from a mixture of micro- or nanometric reactive metals and metal compounds to the mixture theoretical maximum density. An SRM can thus possess a higher energy density, relying on various exothermic reactions, and higher mechanical strength and heat resistance than that of conventional CHNO explosives. Progress in SRM solid studies is reviewed specifically as an energy source for air blast through the reaction of fine SRM fragments under explosive loading. This includes a baseline SRM solid explosion characterization, material properties of an SRM solid, and its dynamic fine fragmentation mechanisms and fragment reaction mechanisms. The overview is portrayed mainly from the author's own experimental studies combined with theoretical and numerical explanation. These advances have laid down some fundamentals for the next stage of developments.

Rhenium ion beam for implantation into semiconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kulevoy, T. V.; Seleznev, D. N.; Alyoshin, M. E.

2012-02-15

At the ion source test bench in Institute for Theoretical and Experimental Physics the program of ion source development for semiconductor industry is in progress. In framework of the program the Metal Vapor Vacuum Arc ion source for germanium and rhenium ion beam generation was developed and investigated. It was shown that at special conditions of ion beam implantation it is possible to fabricate not only homogenous layers of rhenium silicides solid solutions but also clusters of this compound with properties of quantum dots. At the present moment the compound is very interesting for semiconductor industry, especially for nanoelectronics andmore » nanophotonics, but there is no very developed technology for production of nanostructures (for example quantum sized structures) with required parameters. The results of materials synthesis and exploration are presented.« less

Production of magnesium metal

DOEpatents

Blencoe, James G [Harriman, TN; Anovitz, Lawrence M [Knoxville, TN; Palmer, Donald A [Oliver Springs, TN; Beard, James S [Martinsville, VA

2010-02-23

A process of producing magnesium metal includes providing magnesium carbonate, and reacting the magnesium carbonate to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The carbon dioxide is used as a reactant in a second process. In another embodiment of the process, a magnesium silicate is reacted with a caustic material to produce magnesium hydroxide. The magnesium hydroxide is reacted with a source of carbon dioxide to produce magnesium carbonate. The magnesium carbonate is reacted to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The invention further relates to a process for production of magnesium metal or a magnesium compound where an external source of carbon dioxide is not used in any of the reactions of the process. The invention also relates to the magnesium metal produced by the processes described herein.

Pharmacotherapeutic targets in Alzheimer's disease

PubMed Central

Biran, Yif'at; Masters, Colin L; Barnham, Kevin J; Bush, Ashley I; Adlard, Paul A

2009-01-01

Abstract Alzheimer's disease (AD) is a progressive neurodegenerative disorder which is characterized by an increasing impairment in normal memory and cognitive processes that significantly diminishes a person's daily functioning. Despite decades of research and advances in our understanding of disease aetiology and pathogenesis, there are still no effective disease-modifying drugs available for the treatment of AD. However, numerous compounds are currently undergoing pre-clinical and clinical evaluations. These candidate pharma-cotherapeutics are aimed at various aspects of the disease, such as the microtubule-associated τ-protein, the amyloid-β (Aβ) peptide and metal ion dyshomeostasis – all of which are involved in the development and progression of AD. We will review the way these pharmacological strategies target the biochemical and clinical features of the disease and the investigational drugs for each category. PMID:19040415

Two-Center/Three-Electron Sigma Half-Bonds in Main Group and Transition Metal Chemistry.

PubMed

Berry, John F

2016-01-19

First proposed in a classic Linus Pauling paper, the two-center/three-electron (2c/3e) σ half-bond challenges the extremes of what may or may not be considered a chemical bond. Two electrons occupying a σ bonding orbital and one electron occupying the antibonding σ* orbital results in bond orders of ∼0.5 that are characteristic of metastable and exotic species, epitomized in the fleetingly stable He2(+) ion. In this Account, I describe the use of coordination chemistry to stabilize such fugacious three-electron bonded species at disparate ends of the periodic table. A recent emphasis in the chemistry of metal-metal bonds has been to prepare compounds with extremely short metal-metal distances and high metal-metal bond orders. But similar chemistry can be used to explore metal-metal bond orders less than one, including 2c/3e half-bonds. Bimetallic compounds in the Ni2(II,III) and Pd2(II,III) oxidation states were originally examined in the 1980s, but the evidence collected at that time suggested that they did not contain 2c/3e σ bonds. Both classes of compounds have been re-examined using EPR spectroscopy and modern computational methods that show the unpaired electron of each compound to occupy a M-M σ* orbital, consistent with 2c/3e Ni-Ni and Pd-Pd σ half-bonds. Elsewhere on the periodic table, a seemingly unrelated compound containing a trigonal bipyramidal Cu3S2 core caused a stir, leaving prominent theorists at odds with one another as to whether the compound contains a S-S bond. Due to my previous experience with 2c/3e metal-metal bonds, I suggested that the Cu3S2 compound could contain a 2c/3e S-S σ half-bond in the previously unknown oxidation state of S2(3-). By use of the Cambridge Database, a number of other known compounds were identified as potentially containing S2(3-) ligands, including a noteworthy set of cyclopentadienyl-supported compounds possessing diamond-shaped Ni2E2 units with E = S, Se, and Te. These compounds were subjected to extensive studies using X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, density functional theory, and wave function-based computational methods, as well as chemical oxidation and reduction. The compounds contain E-E 2c/3e σ half-bonds and unprecedented E2(3-) "subchalcogenide" ligands, ushering in a new oxidation state paradigm for transition metal-chalcogen chemistry.

Production of magnesium metal

DOEpatents

Blencoe, James G [Harriman, TN; Anovitz, Lawrence M [Knoxville, TN; Palmer, Donald A [Oliver Springs, TN; Beard, James S [Martinsville, VA

2012-04-10

A process of producing magnesium metal includes providing magnesium carbonate, and reacting the magnesium carbonate to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The carbon dioxide is used as a reactant in a second process. In another embodiment of the process, a magnesium silicate is reacted with a caustic material to produce magnesium hydroxide. The magnesium hydroxide is reacted with a source of carbon dioxide to produce magnesium carbonate. The magnesium carbonate is reacted to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The invention also relates to the magnesium metal produced by the processes described herein.

Catalyst for Oxidation of Volatile Organic Compounds

NASA Technical Reports Server (NTRS)

Wood, George M. (Inventor); Upchurch, Billy T. (Inventor); Schryer, David R. (Inventor); Davis, Patricia P. (Inventor); Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); Schyryer, Jacqueline L. (Inventor); DAmbrosia, Christine M. (Inventor)

2000-01-01

Disclosed is a process for oxidizing volatile organic compounds to carbon dioxide and water with the minimal addition of energy. A mixture of the volatile organic compound and an oxidizing agent (e.g. ambient air containing the volatile organic compound) is exposed to a catalyst which includes a noble metal dispersed on a metal oxide which possesses more than one oxidation state. Especially good results are obtained when the noble metal is platinum, and the metal oxide which possesses more than one oxidation state is tin oxide. A promoter (i.e., a small amount of an oxide of a transition series metal) may be used in association with the tin oxide to provide very beneficial results.

Production method for making rare earth compounds

DOEpatents

McCallum, R.W.; Ellis, T.W.; Dennis, K.W.; Hofer, R.J.; Branagan, D.J.

1997-11-25

A method of making a rare earth compound, such as a earth-transition metal permanent magnet compound, without the need for producing rare earth metal as a process step, comprises carbothermically reacting a rare earth oxide to form a rare earth carbide and heating the rare earth carbide, a compound-forming reactant (e.g., a transition metal and optional boron), and a carbide-forming element (e.g., a refractory metal) that forms a carbide that is more thermodynamically favorable than the rare earth carbide whereby the rare earth compound (e.g., Nd{sub 2}Fe{sub 14}B or LaNi{sub 5}) and a carbide of the carbide-forming element are formed.

Production method for making rare earth compounds

DOEpatents

McCallum, R. William; Ellis, Timothy W.; Dennis, Kevin W.; Hofer, Robert J.; Branagan, Daniel J.

1997-11-25

A method of making a rare earth compound, such as a earth-transition metal permanent magnet compound, without the need for producing rare earth metal as a process step, comprises carbothermically reacting a rare earth oxide to form a rare earth carbide and heating the rare earth carbide, a compound-forming reactant (e.g. a transition metal and optional boron), and a carbide-forming element (e.g. a refractory metal) that forms a carbide that is more thermodynamically favorable than the rare earth carbide whereby the rare earth compound (e.g. Nd.sub.2 Fe.sub.14 B or LaNi.sub.5) and a carbide of the carbide-forming element are formed.

Kinetics of heavy metal inhibition of 1,2-dichloroethane biodegradation in co-contaminated water.

PubMed

Arjoon, Ashmita; Olaniran, Ademola Olufolahan; Pillay, Balakrishna

2015-03-01

Sites co-contaminated with heavy metals and 1,2-DCA may pose a greater challenge for bioremediation, as the heavy metals could inhibit the activities of microbes involved in biodegradation. Therefore, this study was undertaken to quantitatively assess the effects of heavy metals (arsenic, cadmium, mercury, and lead) on 1,2-DCA biodegradation in co-contaminated water. The minimum inhibitory concentrations (MICs) and concentrations of the heavy metals that caused half-life doubling (HLDs) of 1,2-DCA as well as the degradation rate coefficient (k(1)) and half-life (t(½)) of 1,2-DCA were measured and used to predict the toxicity of the heavy metals in the water microcosms. An increase in heavy metal concentration resulted in a progressive increase in the t(½) and relative t(½) and a decrease in k(1). The MICs and HLDs of the heavy metals were found to vary, depending on the heavy metals type. In addition, the presence of heavy metals was shown to inhibit 1,2-DCA biodegradation in a dose-dependent manner, with the following order of decreasing inhibitory effect: Hg(2+)  > As(3+)  > Cd(2+)  > Pb(2+). Findings from this study have significant implications for the development of bioremediation strategies for effective degradation of 1,2-DCA and other related compounds in wastewater co-contaminated with heavy metals. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Production of metals and compounds by radiation chemistry

NASA Technical Reports Server (NTRS)

Marsik, S. J.; Philipp, W. H.

1969-01-01

Preparation of metals and compounds by radiation induced chemical reactions involves irradiation of metal salt solutions with high energy electrons. This technique offers a method for the preparation of high purity metals with minimum contamination from the container material or the cover gas.

Technique for detecting liquid metal leaks

DOEpatents

Bauerle, James E.

1979-01-01

In a system employing flowing liquid metal as a heat transfer medium in contact with tubular members containing a working fluid, i.e., steam, liquid metal leaks through the wall of the tubular member are detected by dislodging the liquid metal compounds forming in the tubular member at the leak locations and subsequently transporting the dislodged compound in the form of an aerosol to a detector responsive to the liquid metal compound. In the application to a sodium cooled tubular member, the detector would consist of a sodium responsive device, such as a sodium ion detector.

A Review on Disorder-Driven Metal-Insulator Transition in Crystalline Vacancy-Rich GeSbTe Phase-Change Materials.

PubMed

Wang, Jiang-Jing; Xu, Ya-Zhi; Mazzarello, Riccardo; Wuttig, Matthias; Zhang, Wei

2017-07-27

Metal-insulator transition (MIT) is one of the most essential topics in condensed matter physics and materials science. The accompanied drastic change in electrical resistance can be exploited in electronic devices, such as data storage and memory technology. It is generally accepted that the underlying mechanism of most MITs is an interplay of electron correlation effects (Mott type) and disorder effects (Anderson type), and to disentangle the two effects is difficult. Recent progress on the crystalline Ge₁Sb₂Te₄ (GST) compound provides compelling evidence for a disorder-driven MIT. In this work, we discuss the presence of strong disorder in GST, and elucidate its effects on electron localization and transport properties. We also show how the degree of disorder in GST can be reduced via thermal annealing, triggering a disorder-driven metal-insulator transition. The resistance switching by disorder tuning in crystalline GST may enable novel multilevel data storage devices.

Sensing and capture of toxic and hazardous gases and vapors by metal-organic frameworks.

PubMed

Wang, Hao; Lustig, William P; Li, Jing

2018-03-13

Toxic and hazardous chemical species are ubiquitous, predominantly emitted by anthropogenic activities, and pose serious risks to human health and the environment. Thus, the sensing and subsequent capture of these chemicals, especially in the gas or vapor phase, are of extreme importance. To this end, metal-organic frameworks have attracted significant interest, as their high porosity and wide tunability make them ideal for both applications. These tailorable framework materials are particularly promising for the specific sensing and capture of targeted chemicals, as they can be designed to fit a diverse range of required conditions. This review will discuss the advantages of metal-organic frameworks in the sensing and capture of harmful gases and vapors, as well as principles and strategies guiding the design of these materials. Recent progress in the luminescent detection of aromatic and aliphatic volatile organic compounds, toxic gases, and chemical warfare agents will be summarized, and the adsorptive removal of fluorocarbons/chlorofluorocarbons, volatile radioactive species, toxic industrial gases and chemical warfare agents will be discussed.

Metal-organic frameworks as biosensors for luminescence-based detection and imaging

PubMed Central

Miller, Sophie E.; Teplensky, Michelle H.; Moghadam, Peyman Z.; Fairen-Jimenez, David

2016-01-01

Metal-organic frameworks (MOFs), formed by the self-assembly of metal centres or clusters and organic linkers, possess many key structural and chemical features that have enabled them to be used in sensing platforms for a variety of environmentally, chemically and biomedically relevant compounds. In particular, their high porosity, large surface area, tuneable chemical composition, high degree of crystallinity, and potential for post-synthetic modification for molecular recognition make MOFs promising candidates for biosensing applications. In this review, we separate our discussion of MOF biosensors into two categories: quantitative sensing, focusing specifically on luminescence-based sensors for the direct measurement of a specific analyte, and qualitative sensing, where we describe MOFs used for fluorescence microscopy and as magnetic resonance imaging contrast agents. We highlight several key publications in each of these areas, concluding that MOFs present an exciting, versatile new platform for biosensing applications and imaging, and we expect to see their usage grow as the field progresses. PMID:27499847

Full-scale agricultural biogas plant metal content and process parameters in relation to bacterial and archaeal microbial communities over 2.5 year span.

PubMed

Repinc, Sabina Kolbl; Šket, Robert; Zavec, Domen; Mikuš, Katarina Vogel; Fermoso, Fernando G; Stres, Blaž

2018-05-01

A start-up of 4 MW agricultural biogas plant in Vučja vas, Slovenia, was monitored from 2011 to 2014. The start-up was carried out in 3 weeks with the intake of biomass from three operating full-scale 1-2 MW donor agricultural biogas plants. The samples were taken from donor digesters and from two serial digesters during the start-up over the course of 2.5 years. Bacterial and Archaeal microbial communities progressively diverged from the composition of donor digesters during the start-up phase. The rate of change of Bacterial community decreased exponentially over the first 2.5 years as dynamics within the first 70 days was comparable to that of the next 1.5 years, whereas approximately constant rate was observed for Archaea. Despite rearrangements, the microbial communities remained functionally stable and produced biogas throughout the whole 2.5 years of observation. All systems parameters measured were ordered according to their Kernel density (Gaussian function) ranging from the most dispersed (substrate categories used as cosubstrates, quantities of each cosubstrate, substate dry and volatile matter, process parameters) towards progressively least dispersed (trace metal and ion profiles, aromatic-polyphenolic compounds, biogas plant functional output (energy)). No deficiency was detected in trace metal content as the distribution of metals and elements fluctuated within the suggested limits for biogas over 2.5 year observation. In contrast to the recorded process variables, Bacterial and Archaeal microbial communities exhibited directed changes oriented in time. Variation partitioning showed that a large fraction of variability in the Bacterial and Archaeal microbial communities (55% and 61%, respectively) remained unexplained despite numerous measured variables (n = 44) and stable biogas production. Our results show that the observed reorganization of microbial communities was not directly associated with impact on the full-scale biogas reactor performance. Novel parameters need to be determined to elucidate the variables directly associated with the reorganization of microbial communities and those relevant for sustained function such as the more in-depth interaction between TSOC, trace metal profiles, aromatic-polyphenolic compounds and ionic strength (e.g. electrical conductivity). Copyright © 2018 Elsevier Ltd. All rights reserved.

Hydrogen storage materials and method of making by dry homogenation

DOEpatents

Jensen, Craig M.; Zidan, Ragaiy A.

2002-01-01

Dry homogenized metal hydrides, in particular aluminum hydride compounds, as a material for reversible hydrogen storage is provided. The reversible hydrogen storage material comprises a dry homogenized material having transition metal catalytic sites on a metal aluminum hydride compound, or mixtures of metal aluminum hydride compounds. A method of making such reversible hydrogen storage materials by dry doping is also provided and comprises the steps of dry homogenizing metal hydrides by mechanical mixing, such as be crushing or ball milling a powder, of a metal aluminum hydride with a transition metal catalyst. In another aspect of the invention, a method of powering a vehicle apparatus with the reversible hydrogen storage material is provided.

Process for making a noble metal on tin oxide catalyst

NASA Technical Reports Server (NTRS)

Upchurch, Billy T. (Inventor); Davis, Patricia (Inventor); Miller, Irvin M. (Inventor)

1989-01-01

A quantity of reagent grade tin metal or compound, chloride-free, and high-surface-area silica spheres are placed in deionized water, followed by deaerating the mixture by boiling and adding an oxidizing agent, such as nitric acid. The nitric acid oxidizes the tin to metastannic acid which coats the spheres because the acid is absorbed on the substrate. The metastannic acid becomes tin oxide upon drying and calcining. The tin-oxide coated silica spheres are then placed in water and boiled. A chloride-free precious metal compound in aqueous solution is then added to the mixture containing the spheres, and the precious metal compound is reduced to a precious metal by use of a suitable reducing agent such as formic acid. Very beneficial results were obtained using the precious metal compound tetraammine platinum(II) hydroxide.

Aerosol chemical vapor deposition of metal oxide films

DOEpatents

Ott, Kevin C.; Kodas, Toivo T.

1994-01-01

A process of preparing a film of a multicomponent metal oxide including: forming an aerosol from a solution comprised of a suitable solvent and at least two precursor compounds capable of volatilizing at temperatures lower than the decomposition temperature of said precursor compounds; passing said aerosol in combination with a suitable oxygen-containing carrier gas into a heated zone, said heated zone having a temperature sufficient to evaporate the solvent and volatilize said precursor compounds; and passing said volatilized precursor compounds against the surface of a substrate, said substrate having a sufficient temperature to decompose said volatilized precursor compounds whereby metal atoms contained within said volatilized precursor compounds are deposited as a metal oxide film upon the substrate is disclosed. In addition, a coated article comprising a multicomponent metal oxide film conforming to the surface of a substrate selected from the group consisting of silicon, magnesium oxide, yttrium-stabilized zirconium oxide, sapphire, or lanthanum gallate, said multicomponent metal oxide film characterized as having a substantially uniform thickness upon said FIELD OF THE INVENTION The present invention relates to the field of film coating deposition techniques, and more particularly to the deposition of multicomponent metal oxide films by aerosol chemical vapor deposition. This invention is the result of a contract with the Department of Energy (Contract No. W-7405-ENG-36).

[Exposure to metal compounds in occupational galvanic processes].

PubMed

Surgiewicz, Jolanta; Domański, Wojciech

2006-01-01

Occupational galvanic processes are provided in more than 600 small and medium enterprises in Poland. Workers who deal with galvanic coating are exposed to heavy metal compounds: tin, silver, copper and zinc. Some of them are carcinogenic, for example, hexavalent chromium compounds, nickel and cadmium compounds. Research covered several tens of workstations involved in chrome, nickel, zinc, tin, silver, copper and cadmium plating. Compounds of metals present in the air were determined: Cr, Ni, Cd, Sn, Ag--by atomic absorption spectrometry with electrothermal atomization (ET-AAS) and Zn--by atomic absorption spectrometry with flame atomization (F-AAS). The biggest metal concentrations--of silver and copper--were found at workstations of copper, brass, cadmium, nickel and chrome plating, conducted at the same time. Significant concentrations of copper were found at workstations of maintenance bathing and neutralizing of sewage. The concentrations of metals did not exceed Polish MAC values. MAC values were not exceeded for carcinogenic chromium(VI), nickel or cadmium, either. In galvanic processes there was no hazard related to single metals or their compounds, even carcinogenic ones. Combined exposure indicators for metals at each workstation did not exceed 1, either. However, if there are even small quantities of carcinogenic agents, health results should always be taken into consideration.

Metal alkoxides and methods of making same

DOEpatents

Hentges, Patrick J.; Greene, Laura H.; Pafford, Margaret Mary; Westwood, Glenn; Klemperer, Walter G.

2005-01-04

A method of making a superconducting structure includes depositing a metal alkoxide on a surface of a metal and hydrolyzing the metal alkoxide on the surface to form a pinhole-free film. The metal is a superconductor. The metal alkoxide may be a compound of formula (I): where M is zirconium or hafnium, and the purity of the compound is at least 97% as measured by NMR spectroscopy.

Intriguing optoelectronic properties of metal halide perovskites

DOE PAGES

Manser, Joseph S.; Christians, Jeffrey A.; Kamat, Prashant V.

2016-06-21

Here, a new chapter in the long and distinguished history of perovskites is being written with the breakthrough success of metal halide perovskites (MHPs) as solution-processed photovoltaic (PV) absorbers. The current surge in MHP research has largely arisen out of their rapid progress in PV devices; however, these materials are potentially suitable for a diverse array of optoelectronic applications. Like oxide perovskites, MHPs have ABX 3 stoichiometry, where A and B are cations and X is a halide anion. Here, the underlying physical and photophysical properties of inorganic (A = inorganic) and hybrid organic-inorganic (A = organic) MHPs are reviewedmore » with an eye toward their potential application in emerging optoelectronic technologies. Significant attention is given to the prototypical compound methylammonium lead iodide (CH 3NH 3PbI 3) due to the preponderance of experimental and theoretical studies surrounding this material. We also discuss other salient MHP systems, including 2- dimensional compounds, where relevant. More specifically, this review is a critical account of the interrelation between MHP electronic structure, absorption, emission, carrier dynamics and transport, and other relevant photophysical processes that have propelled these materials to the forefront of modern optoelectronics research.« less

Two-dimensional triangular lattice and its application to lithium-intercalated layered compounds

NASA Astrophysics Data System (ADS)

Decerqueira, R. O.

1982-08-01

Good rechargeable batteries are being searched for use in electric vehicles and in energy storage during off-peak consumption periods and from solar sources. The interest in lithium intercalation compounds has been recently enhanced by the search for such batteries. The process of intercalation of lithium in several transition metal dichalcogenides can provide an emf of several volts. The progress achieved in the last decade in the investigation of these intercalates has been facilitated by the availability of the dichalcogenides as single crystals and by their chemical stability. The transition-metal dichalcogenides and their Li-intercalates are studied, with emphasis on the Li/su xTa/sub yTi/sub l-y/S2 series. The interactions between the Li atoms and the applicability of a lattice gas model to the problem of ordering of these atoms is discussed. A formulation is presented of the cluster-variation aproximation to the lattice gas problem. The single-site and the nearest-neighbor triangle basic clusters are considered as models for Li/sub x TiS2. Also a theory is presented for the effects of a random distribution of different species of host atoms, as in Ta/sub y/Ti/sub l-y/S2.

Oxidative Addition and Reductive Elimination at Main-Group Element Centers.

PubMed

Chu, Terry; Nikonov, Georgii I

2018-04-11

Oxidative addition and reductive elimination are key steps in a wide variety of catalytic reactions mediated by transition-metal complexes. Historically, this reactivity has been considered to be the exclusive domain of d-block elements. However, this paradigm has changed in recent years with the demonstration of transition-metal-like reactivity by main-group compounds. This Review highlights the substantial progress achieved in the past decade for the activation of robust single bonds by main-group compounds and the more recently realized activation of multiple bonds by these elements. We also discuss the significant discovery of reversible activation of single bonds and distinct examples of reductive elimination at main-group element centers. The review consists of three major parts, starting with oxidative addition of single bonds, proceeding to cleavage of multiple bonds, and culminated by the discussion of reversible bond activation and reductive elimination. Within each subsection, the discussion is arranged according to the type of bond being cleaved or formed and considers elements from the left to the right of each period and down each group of the periodic table. The majority of results discussed in this Review come from the past decade; however, earlier reports are also included to ensure completeness.

Biosynthetic inorganic chemistry.

PubMed

Lu, Yi

2006-08-25

Inorganic chemistry and biology can benefit greatly from each other. Although synthetic and physical inorganic chemistry have been greatly successful in clarifying the role of metal ions in biological systems, the time may now be right to utilize biological systems to advance coordination chemistry. One such example is the use of small, stable, easy-to-make, and well-characterized proteins as ligands to synthesize novel inorganic compounds. This biosynthetic inorganic chemistry is possible thanks to a number of developments in biology. This review summarizes the progress in the synthesis of close models of complex metalloproteins, followed by a description of recent advances in using the approach for making novel compounds that are unprecedented in either inorganic chemistry or biology. The focus is mainly on synthetic "tricks" learned from biology, as well as novel structures and insights obtained. The advantages and disadvantages of this biosynthetic approach are discussed.

Tetratopic phenyl compounds, related metal-organic framework materials and post-assembly elaboration

DOEpatents

Farha, Omar K.; Hupp, Joseph T.

2012-09-11

Disclosed are tetratopic carboxylic acid phenyl for use in metal-organic framework compounds. These compounds are useful in catalysis, gas storage, sensing, biological imaging, drug delivery and gas adsorption separation.

Tetratopic phenyl compounds, related metal-organic framework materials and post-assembly elaboration

DOEpatents

Farha, Omar K; Hupp, Joseph T

2013-06-25

Disclosed are tetratopic carboxylic acid phenyl for use in metal-organic framework compounds. These compounds are useful in catalysis, gas storage, sensing, biological imaging, drug delivery and gas adsorption separation.

Polyorganometallosiloxane-2- or -4-pyridine coatings

DOEpatents

Sugama, Toshifumi

1997-01-01

A new family of polyorganometallosiloxane-2- or -4-pyridine compounds are provided for corrosion resistant coatings on light metals such as aluminum, magnesium, zinc, steel and their allows. The novel compounds contain backbones modified by metal alkoxides, metallocenes and metallophthalocyanates where the metal is Zr, Ti, Mo, V, Hf, Nb, Si, B and combinations thereof. Methods of making the new compounds are also provided.

Inert electrode composition having agent for controlling oxide growth on electrode made therefrom

DOEpatents

Ray, S.P.

1986-04-15

An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily. The electrode composition further includes a metal compound dopant which will aid in controlling the thickness of a protective oxide layer on at least the bottom portion of an electrode made therefrom during use. 12 figs.

Inert electrode composition having agent for controlling oxide growth on electrode made therefrom

DOEpatents

Ray, Siba P.

1986-01-01

An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily. The electrode composition further includes a metal compound dopant which will aid in controlling the thickness of a protective oxide layer on at least the bottom portion of an electrode made therefrom during use.

Induction slag reduction process for purifying metals

DOEpatents

Traut, Davis E.; Fisher, II, George T.; Hansen, Dennis A.

1991-01-01

A continuous method is provided for purifying and recovering transition metals such as neodymium and zirconium that become reactive at temperatures above about 500.degree. C. that comprises the steps of contacting the metal ore with an appropriate fluorinating agent such as an alkaline earth metal fluosilicate to form a fluometallic compound, and reducing the fluometallic compound with a suitable alkaline earth or alkali metal compound under molten conditions, such as provided in an induction slag metal furnace. The method of the invention is advantageous in that it is simpler and less expensive than methods used previously to recover pure metals, and it may be employed with a wide range of transition metals that were reactive with enclosures used in the prior art methods and were hard to obtain in uncontaminated form.

High surface area graphene-supported metal chalcogenide assembly

DOEpatents

Worsley, Marcus A.; Kuntz, Joshua D.; Orme, Christine A.

2017-04-25

Disclosed here is a method for hydrocarbon conversion, comprising contacting at least one graphene-supported assembly with at least one hydrocarbon feedstock, wherein the graphene-supported assembly comprises (i) a three-dimensional network of graphene sheets crosslinked by covalent carbon bonds and (ii) at least one metal chalcogenide compound disposed on the graphene sheets, wherein the chalcogen of the metal chalcogenide compound is selected from S, Se and Te, and wherein the metal chalcogenide compound accounts for at least 20 wt. % of the graphene-supported assembly.

Plastic scintillators with high loading of one or more metal carboxylates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cherepy, Nerine; Sanner, Robert Dean

In one embodiment, a material includes at least one metal compound incorporated into a polymeric matrix, where the metal compound includes a metal and one or more carboxylate ligands, where at least one of the one or more carboxylate ligands includes a tertiary butyl group, and where the material is optically transparent. In another embodiment, a method includes: processing pulse traces corresponding to light pulses from a scintillator material; and outputting a result of the processing, where the scintillator material comprises at least one metal compound incorporated into a polymeric matrix, the at least one metal compound including a metalmore » and one or more carboxylate ligands, where at least one of the one or more carboxylate ligands has a tertiary butyl group, and where the scintillator material is optically transparent and has an energy resolution at 662 keV of less than about 20%.« less

ET Toxic Metals Replacement Review SEA Spring Face to Face

NASA Technical Reports Server (NTRS)

Pratz, Earl

2007-01-01

The information contained in the presentation covers development work carried out under SDS projects. The intent of the effort is to find chrome(VI) free alternates to our current chromated processing solutions. The information presented reports progress in work aimed to replace our alkaline cleaner (Turco 4215), conversion coat (Iridite 14-2) and chrome (VI) compounds used in LOx tank hydrostatic proof test solution. To date we have found candidates for use in the proof test solution and alkaline cleaner. These candidates are in the final stages of testing. Lab data is reported in the presentation.

Polyorganometallosiloxane-2- or -4-pyridine coatings

DOEpatents

Sugama, T.

1997-12-30

A new family of polyorganometallosiloxane-2- or -4-pyridine compounds are provided for corrosion resistant coatings on light metals such as aluminum, magnesium, zinc, steel and their alloys. The novel compounds contain backbones modified by metal alkoxides, metallocenes and metallophthalocyanates where the metal is Zr, Ti, Mo, V, Hf, Nb, Si, B and combinations thereof. Methods of making the new compounds are also provided. 13 figs.

Investigation of metal-dithiolate fold angle effects: implications for molybdenum and tungsten enzymes.

PubMed

Joshi, Hemant K; Cooney, J Jon A; Inscore, Frank E; Gruhn, Nadine E; Lichtenberger, Dennis L; Enemark, John H

2003-04-01

Gas-phase photoelectron spectroscopy and density functional theory have been used to investigate the interactions between the sulfur pi-orbitals of arene dithiolates and high-valent transition metals as minimum molecular models of the active site features of pyranopterin MoW enzymes. The compounds (Tp*)MoO(bdt) (compound 1), Cp(2)Mo(bdt) (compound 2), and Cp(2)Ti(bdt) (compound 3) [where Tp* is hydrotris(3,5-dimethyl-1-pyrazolyl)borate, bdt is 1,2-benzenedithiolate, and Cp is eta(5)- cyclopentadienyl] provide access to three different electronic configurations of the metal, formally d(1), d(2), and d(0), respectively. The gas-phase photoelectron spectra show that ionizations from occupied metal and sulfur based valence orbitals are more clearly observed in compounds 2 and 3 than in compound 1. The observed ionization energies and characters compare very well with those calculated by density functional theory. A "dithiolate-folding-effect" involving an interaction of the metal in-plane and sulfur-pi orbitals is proposed to be a factor in the electron transfer reactions that regenerate the active sites of molybdenum and tungsten enzymes.

Stabilizing metal components in electrodes of electrochemical cells

DOEpatents

Spengler, Charles J.; Ruka, Roswell J.

1989-01-01

Disclosed is a method of reducing the removal or transfer into a gas phase of a current carrying metal in an apparatus, such as an electrochemical cell 2 having a porous fuel electrode 6 containing metal particles 11, where the metal is subject to removal or transfer into a gaseous phase, the method characterized in that (1) a metal organic compound that decomposes to form an electronically conducting oxide coating when heated is applied to the metal and porous electrode, and (2) the compound on the metal is then heated to a temperature sufficient to decompose the compound into an oxide coating 13 by increasing the temperature at a rate that is longer than 1 hour between room temperature and 600.degree. C., resulting in at least one continuous layer 13, 14 of the oxide coating on the metal.

Potential value of phosphate compounds in enhancing immobilization and reducing bioavailability of mixed heavy metal contaminants in shooting range soil.

PubMed

Seshadri, B; Bolan, N S; Choppala, G; Kunhikrishnan, A; Sanderson, P; Wang, H; Currie, L D; Tsang, Daniel C W; Ok, Y S; Kim, G

2017-10-01

Shooting range soils contain mixed heavy metal contaminants including lead (Pb), cadmium (Cd), and zinc (Zn). Phosphate (P) compounds have been used to immobilize these metals, particularly Pb, thereby reducing their bioavailability. However, research on immobilization of Pb's co-contaminants showed the relative importance of soluble and insoluble P compounds, which is critical in evaluating the overall success of in situ stabilization practice in the sustainable remediation of mixed heavy metal contaminated soils. Soluble synthetic P fertilizer (diammonium phosphate; DAP) and reactive (Sechura; SPR) and unreactive (Christmas Island; CPR) natural phosphate rocks (PR) were tested for Cd, Pb and Zn immobilization and later their mobility and bioavailability in a shooting range soil. The addition of P compounds resulted in the immobilization of Cd, Pb and Zn by 1.56-76.2%, 3.21-83.56%, and 2.31-74.6%, respectively. The reactive SPR significantly reduced Cd, Pb and Zn leaching while soluble DAP increased their leachate concentrations. The SPR reduced the bioaccumulation of Cd, Pb and Zn in earthworms by 7.13-23.4% and 14.3-54.6% in comparison with earthworms in the DAP and control treatment, respectively. Bioaccessible Cd, Pb and Zn concentrations as determined using a simplified bioaccessibility extraction test showed higher long-term stability of P-immobilized Pb and Zn than Cd. The differential effect of P-induced immobilization between P compounds and metals is due to the variation in the solubility characteristics of P compounds and nature of metal phosphate compounds formed. Therefore, Pb and Zn immobilization by P compounds is an effective long-term remediation strategy for mixed heavy metal contaminated soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrothermal alkali metal catalyst recovery process

DOEpatents

Eakman, James M.; Clavenna, LeRoy R.

1979-01-01

In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles primarily in the form of water soluble alkali metal formates by treating the particles with a calcium or magnesium-containing compound in the presence of water at a temperature between about 250.degree. F. and about 700.degree. F. and in the presence of added carbon monoxide. During the treating process the water insoluble alkali metal compounds comprising the insoluble alkali metal residues are converted into water soluble alkali metal formates. The resultant aqueous solution containing water soluble alkali metal formates is then separated from the treated particles and any insoluble materials formed during the treatment process, and recycled to the gasification process where the alkali metal formates serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst. This process permits increased recovery of alkali metal constituents, thereby decreasing the overall cost of the gasification process by reducing the amount of makeup alkali metal compounds necessary.

Atomic layer deposition of metal sulfide thin films using non-halogenated precursors

DOEpatents

Martinson, Alex B. F.; Elam, Jeffrey W.; Pellin, Michael J.

2015-05-26

A method for preparing a metal sulfide thin film using ALD and structures incorporating the metal sulfide thin film. The method includes providing an ALD reactor, a substrate, a first precursor comprising a metal and a second precursor comprising a sulfur compound. The first and the second precursors are reacted in the ALD precursor to form a metal sulfide thin film on the substrate. In a particular embodiment, the metal compound comprises Bis(N,N'-di-sec-butylacetamidinato)dicopper(I) and the sulfur compound comprises hydrogen sulfide (H.sub.2S) to prepare a Cu.sub.2S film. The resulting metal sulfide thin film may be used in among other devices, photovoltaic devices, including interdigitated photovoltaic devices that may use relatively abundant materials for electrical energy production.

Elevated levels of ferrimagnetic metals in foodchains supporting the Guam cluster of neurodegeneration: do metal nucleated crystal contaminants [corrected] evoke magnetic fields that initiate the progressive pathogenesis of neurodegeneration?

PubMed

Purdey, Mark

2004-01-01

Elevated levels of aluminium (Al), strontium (Sr), barium (Ba), iron (Fe), manganese (Mn) cations - combined with deficiencies of magnesium (Mg)/calcium (Ca) - have been observed in the foodchains that traditionally support the Chamorro populations affected by high incidence clusters of Alzheimer (AD), Parkinson-like (PD), motor neurone diseases and multiple sclerosis on the island of Guam. Soils drawn from the cluster region demonstrated an excessive fivefold increase in 'magnetic susceptibility' readings in relation to soils from disease free adjoining regions. A multifactorial aetiological hypothesis is proposed that pivots upon the combined exposure to high levels of natural/industrial sources of ferrimagnetic/ferroelectric compounds incorporating Al, Fe, Mn, Sr, Ba (e.g., via yam/seafood consumption or exposure to world war 2 (WW2) munitions) and to low levels of Mg/Ca in all S. Pacific locations where these clusters of neurodegenerative disease have simultaneously erupted. Once gut/blood brain barrier permeability is impaired, the increased uptake of Al, Fe, Sr, Ba, or Mn into the Mg/Ca depleted brain leads to rogue metal substitutions at the Mg/Ca vacated binding domains on various enzyme/proteoglycan groups, causing a broad ranging disruption in Mg/Ca dependent systems - such as the glutamine synthetase which prevents the accumulation of neurotoxic glutamate. The rogue metals chelate sulphate, disrupting sulphated-proteoglycan mediated inhibition of crystal proliferation, as well as its regulation of the Fibroblast growth factor receptor complex which disturbs the molecular conformation of those receptors and their regulation of transphosphorylation between intracellular kinase domains; ultimately collapsing proteoglycan mediated cell-cell signalling pathways which maintain the growth and structural integrity of the neuronal networks. The depression of Mg/Ca dependent systems in conjunction with the progressive ferrimagnetisation of the CNS due to an overload of rogue ferroelectric/ferrimagnetic metal contaminants, enables 'seeding' of metal-protein crystalline arrays that can proliferate in the proteoglycan depleted brain. The resulting magnetic field emissions initiate a free radical mediated progressive pathogenesis of neurodegeneration. The co-clustering of these various types of disease in select geographical pockets around the world suggests that all of these conditions share a common early life exposure to ferromagnetic metal nucleating agents in their multifactorial aetiology. Factors such as individual genetics, the species of metal involved, etc., dictate which specific class of disease will emerge as a delayed neurotoxic response to these environmental insults.

Chemical plating method of preparing radiation source material

DOEpatents

Smith, P.K.; Huntoon, R.T.; Mosley, W.C. Jr.

1973-12-11

A uniform dispersion of a radioisotope within a noble metal matrix is provided by chemically plating a noble metal coating onto particles including a dissociable compound of the mdioisotope. A suspension of the dissociable compound in a chemically reductive solution is prepared and noble metal cations added to produce the noble metal coatings. The coated particles are filtered, dried and heated to calcine the dissociable compound to a refractory powder. The powder can be encapsulated in measured portions or consolidated and shaped into an elongated form for easy apportionnnent as radiation source material. (Official Gazette)

Smart textile device using ion polymer metal compound.

PubMed

Nakamura, Taro; Ihara, Tadashi

2013-01-01

We have developed a smart textile device that detects angular displacement of attached surface using ion polymer metal compound. The device was composed of ion polymer metal compound (IPMC) which was fabricated from Nafion resin by heat-press and chemical gold plating. The generated voltage from IPMC was measured as a function of bending angle. Fabricated IPMC device was weaved into a cotton cloth and multidirectional movements were detected.

Design of Research on Performance of a New Iridium Coordination Compound for the Detection of Hg2.

PubMed

Ma, Hailing; Tsai, Sang-Bing

2017-10-16

Heavy metal pollution has become one of the most significant pollution problems encountered by our country in terms of environment protection. In addition to the significant effects of heavy metals on the human body and other organisms through water, food chain enrichment and other routes, heavy metals involved in daily necessities beyond the level limit could also affect people's lives, so the detection of heavy metals is extremely important. Ir (III) coordination compound, considered to be one of the best phosphorescent sensing materials, is characterized by high luminous efficiency, easy modification of the ligand and so on, and it has potential applications in the field of heavy metal detection. This project aims to product a new Ir (III) functional coordination compound by designing a new auxiliary ligand and a main ligand with a sulfur identification unit, in order to systematically investigate the application of iridium coordination compound in the detection of the heavy metal Hg 2+ . With the introduction of the sulfur identification unit, selective sensing of Hg 2+ could be achieved. Additionally, a new auxiliary ligand is also introduced to produce a functional iridium coordination compound with high quantum efficiency, and to diversify the application of iridium coordination compound in this field.

Effects of Ga substitution on the structural and magnetic properties of half metallic Fe2MnSi Heusler compound

NASA Astrophysics Data System (ADS)

Pedro, S. S.; Caraballo Vivas, R. J.; Andrade, V. M.; Cruz, C.; Paixão, L. S.; Contreras, C.; Costa-Soares, T.; Caldeira, L.; Coelho, A. A.; Carvalho, A. Magnus G.; Rocco, D. L.; Reis, M. S.

2015-01-01

The so-called half-metallic magnets have been proposed as good candidates for spintronic applications due to the feature of exhibiting a hundred percent spin polarization at the Fermi level. Such materials follow the Slater-Pauling rule, which relates the magnetic moment with the valence electrons in the system. In this paper, we study the bulk polycrystalline half-metallic Fe2MnSi Heusler compound replacing Si by Ga to determine how the Ga addition changes the magnetic, the structural, and the half-metal properties of this compound. The material does not follow the Slater-Pauling rule, probably due to a minor structural disorder degree in the system, but a linear dependence on the magnetic transition temperature with the valence electron number points to the half-metallic behavior of this compound.

40 CFR 423.11 - Specialized definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... not included. (c) The term chemical metal cleaning waste means any wastewater resulting from the cleaning of any metal process equipment with chemical compounds, including, but not limited to, boiler tube... chemical cleaning compounds] any metal process equipment including, but not limited to, boiler tube...

40 CFR 423.11 - Specialized definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... not included. (c) The term chemical metal cleaning waste means any wastewater resulting from the cleaning of any metal process equipment with chemical compounds, including, but not limited to, boiler tube... chemical cleaning compounds] any metal process equipment including, but not limited to, boiler tube...

40 CFR 423.11 - Specialized definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... air conditioning wastes are not included. (c) The term chemical metal cleaning waste means any wastewater resulting from the cleaning of any metal process equipment with chemical compounds, including, but... from cleaning [with or without chemical cleaning compounds] any metal process equipment including, but...

40 CFR 423.11 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... chemical metal cleaning waste means any wastewater resulting from the cleaning of any metal process equipment with chemical compounds, including, but not limited to, boiler tube cleaning. (d) The term metal cleaning waste means any wastewater resulting from cleaning [with or without chemical cleaning compounds...

40 CFR 423.11 - Specialized definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... chemical metal cleaning waste means any wastewater resulting from the cleaning of any metal process equipment with chemical compounds, including, but not limited to, boiler tube cleaning. (d) The term metal cleaning waste means any wastewater resulting from cleaning [with or without chemical cleaning compounds...

A Schiff base-derived copper (II) complex is a potent inducer of apoptosis in colon cancer cells by activating the intrinsic pathway.

PubMed

Hajrezaie, Maryam; Paydar, Mohammadjavad; Moghadamtousi, Soheil Zorofchian; Hassandarvish, Pouya; Gwaram, Nura Suleiman; Zahedifard, Maryam; Rouhollahi, Elham; Karimian, Hamed; Looi, Chung Yeng; Ali, Hapipah Mohd; Abdul Majid, Nazia; Abdulla, Mahmood Ameen

2014-01-01

Metal-based drugs with extensive clinical applications hold great promise for the development of cancer chemotherapeutic agents. In the last few decades, Schiff bases and their complexes have become well known for their extensive biological potential. In the present study, we examined the antiproliferative effect of a copper (II) complex on HT-29 colon cancer cells. The Cu(BrHAP)2 Schiff base compound demonstrated a potent antiproliferative effect in HT-29 cells, with an IC50 value of 2.87  μg/ml after 72 h of treatment. HT-29 cells treated with Cu (II) complexes underwent apoptosis death, as exhibited by a progressive elevation in the proportion of the G1 cell population. At a concentration of 6.25  μg/ml, the Cu(BrHAP)2 compound caused significant elevation in ROS production following perturbation of mitochondrial membrane potential and cytochrome c release, as assessed by the measurement of fluorescence intensity in stained cells. Furthermore, the activation of caspases 3/7 and 9 was part of the Cu (II) complex-induced apoptosis, which confirmed the involvement of mitochondrial-mediated apoptosis. Meanwhile, there was no significant activation of caspase-8. Taken together, these results imply that the Cu(BrHAP)2 compound is a potential candidate for further in vivo and clinical colon cancer studies to develop novel chemotherapeutic agents derived from metal-based agents.

A Schiff Base-Derived Copper (II) Complex Is a Potent Inducer of Apoptosis in Colon Cancer Cells by Activating the Intrinsic Pathway

PubMed Central

Hajrezaie, Maryam; Paydar, Mohammadjavad; Zorofchian Moghadamtousi, Soheil; Hassandarvish, Pouya; Gwaram, Nura Suleiman; Zahedifard, Maryam; Rouhollahi, Elham; Karimian, Hamed; Looi, Chung Yeng; Ali, Hapipah Mohd; Abdul Majid, Nazia; Abdulla, Mahmood Ameen

2014-01-01

Metal-based drugs with extensive clinical applications hold great promise for the development of cancer chemotherapeutic agents. In the last few decades, Schiff bases and their complexes have become well known for their extensive biological potential. In the present study, we examined the antiproliferative effect of a copper (II) complex on HT-29 colon cancer cells. The Cu(BrHAP)2 Schiff base compound demonstrated a potent antiproliferative effect in HT-29 cells, with an IC50 value of 2.87 μg/ml after 72 h of treatment. HT-29 cells treated with Cu (II) complexes underwent apoptosis death, as exhibited by a progressive elevation in the proportion of the G1 cell population. At a concentration of 6.25 μg/ml, the Cu(BrHAP)2 compound caused significant elevation in ROS production following perturbation of mitochondrial membrane potential and cytochrome c release, as assessed by the measurement of fluorescence intensity in stained cells. Furthermore, the activation of caspases 3/7 and 9 was part of the Cu (II) complex-induced apoptosis, which confirmed the involvement of mitochondrial-mediated apoptosis. Meanwhile, there was no significant activation of caspase-8. Taken together, these results imply that the Cu(BrHAP)2 compound is a potential candidate for further in vivo and clinical colon cancer studies to develop novel chemotherapeutic agents derived from metal-based agents. PMID:24737979

Sustainable metal alkynyl chemistry: 3d metals and polyaza macrocyclic ligands.

PubMed

Ren, Tong

2016-02-25

We describe the chemistry of 3d metal alkynyls based on polyaza macrocyclic ligands, an emerging area of alkynyl chemistry that has previously been dominated by 4d and 5d metals with soft ligands. The abundance of 3d metals and low cost of tetraazacyclotetradecane ligands make these compounds more affordable, sustainable alternatives to metal alkynyls based on precious metals. Taking advantage of the rich variety of starting materials available in the literature, trans-[M(cyclam)(C2R)2]X (cyclam = 1,4,8,11-tetraazacyclotetradecane) compounds have been prepared from the reactions between [M(cyclam)X2]X (M = Cr, Fe and Co; X = Cl or OTf) and LiC2R. With [Co(cyclam)Cl2](+), both the {trans-[Co(cyclam)Cl]2(μ-(C≡C)n)}(2+) and trans-[Co(cyclam)(C2R)Cl](+) compounds have been prepared by a dehydrohalogenation reaction. The latter compounds undergo the second alkynylation reaction to afford dissymmetric trans-[Co(cyclam)(C2R)(C2R')](+) compounds. Similar alkynylation chemistry with complexes of the cyclam derivatives TMC (1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) and HMC (5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) has been demonstrated in studies of [Ni(TMC)(C2R)](+) and trans-/cis-[Cr(HMC)(C2R)2](+). Me3TACN (1,4,7-N,N',N''-trimethyl-1,4,7-triazacyclononane) is also a supporting ligand that has been observed in transition metal alkynyls. The trans-[M(cyclam)(C2D)(C2A)](+) compounds (D = donor chromophore, A = acceptor chromophore) are excellent candidates for probing photoinduced electron transfer and related photophysical and photochemical processes. 3d Metal ions are often in high-spin ground states, which make these alkynyl compounds promising building blocks for magnetic materials.

Method and reaction pathway for selectively oxidizing organic compounds

DOEpatents

Camaioni, Donald M.; Lilga, Michael A.

1998-01-01

A method of selectively oxidizing an organic compound in a single vessel comprises: a) combining an organic compound, an acid solution in which the organic compound is soluble, a compound containing two oxygen atoms bonded to one another, and a metal ion reducing agent capable of reducing one of such oxygen atoms, and thereby forming a mixture; b) reducing the compound containing the two oxygen atoms by reducing one of such oxygen atoms with the metal ion reducing agent to, 1) oxidize the metal ion reducing agent to a higher valence state, and 2) produce an oxygen containing intermediate capable of oxidizing the organic compound; c) reacting the oxygen containing intermediate with the organic compound to oxidize the organic compound into an oxidized organic intermediate, the oxidized organic intermediate having an oxidized carbon atom; d) reacting the oxidized organic intermediate with the acid counter ion and higher valence state metal ion to bond the acid counter ion to the oxidized carbon atom and thereby produce a quantity of an ester incorporating the organic intermediate and acid counter ion; and e) reacting the oxidized organic intermediate with the higher valence state metal ion and water to produce a quantity of alcohol which is less than the quantity of ester, the acid counter ion incorporated in the ester rendering the carbon atom bonded to the counter ion less reactive with the oxygen containing intermediate in the mixture than is the alcohol with the oxygen containing intermediate.

Heterogeneous integration of low-temperature metal-oxide TFTs

NASA Astrophysics Data System (ADS)

Schuette, Michael L.; Green, Andrew J.; Leedy, Kevin D.; McCandless, Jonathan P.; Jessen, Gregg H.

2017-02-01

The breadth of circuit fabrication opportunities enabled by metal-oxide thin-film transistors (MO-TFTs) is unprecedented. Large-area deposition techniques and high electron mobility are behind their adoption in the display industry, and substrate agnosticism and low process temperatures enabled the present wave of flexible electronics research. Reports of circuits involving complementaryMO-TFTs, oxide-organic hybrid combinations, and even MO-TFTs integrated onto Si LSI back end of line interconnects demonstrate this technology's utility in 2D and 3D monolithic heterogeneous integration (HI). In addition to a brief literature review focused on functional HI between MO-TFTs and a variety of dissimilar active devices, we share progress toward integrating MO-TFTs with compound semiconductor devices, namely GaN HEMTs. A monolithically integrated cascode topology was used to couple a HEMT's >200 V breakdown characteristic with the gate driving characteristic of an IGZO TFT, effectively shifting the HEMT threshold voltage from -3 V to +1 V.

Metallomics for Alzheimer's disease treatment: Use of new generation of chelators combining metal-cation binding and transport properties.

PubMed

D'Acunto, Cosimo Walter; Kaplánek, Robert; Gbelcová, Helena; Kejík, Zdeněk; Bříza, Tomáš; Vasina, Liudmila; Havlík, Martin; Ruml, Tomáš; Král, Vladimír

2018-04-25

Alzheimer's disease (AD) is a progressive neurodegenerative disorder affecting tens of million people. Currently marketed drugs have limited therapeutic efficacy and only slowing down the neurodegenerative process. Interestingly, it has been suggested that biometal cations in the amyloid beta (Aβ) aggregate deposits contribute to neurotoxicity and degenerative changes in AD. Thus, chelation therapy could represent novel mode of therapeutic intervention. Here we describe the features of chelators with therapeutically relevant mechanism of action. We have found that the tested compounds effectively reduce the toxicity of exogenous Aβ and suppress its endogenous production as well as decrease oxidative stress. Cholyl hydrazones were found to be the most active compounds. In summary, our data show that cation complexation, together with improving transport efficacy may represent basis for eventual treatment strategy in AD. Copyright © 2018. Published by Elsevier Masson SAS.

Volatile organometallic complexes suitable for use in chemical vapor depositions on metal oxide films

DOEpatents

Giolando, Dean M.

2003-09-30

Novel ligated compounds of tin, titanium, and zinc are useful as metal oxide CVD precursor compounds without the detriments of extreme reactivity yet maintaining the ability to produce high quality metal oxide coating by contact with heated substrates.

Redox chromophore compounds and electrodes of metal containing substituted bipyridines

DOEpatents

Elliott, Cecil M.; Redepenning, Jody G.

1986-01-01

Chromophoric compounds, each having a wide range of distinct color changes in response to changes in the oxidation states thereof, are provided in the form of polymerizable monomers, and polymers thereof, of certain metal containing, and electron group substituted, 2,2'-bipyridine compounds.

Method of synthesizing metal doped diamond-like carbon films

NASA Technical Reports Server (NTRS)

Ueno, Mayumi (Inventor); Sunkara, Mahendra Kumar (Inventor)

2003-01-01

A method of synthesizing metal doped carbon films by placing a substrate in a chamber with a selected amount of a metalorganic compound. An electron cyclotron resonance is applied to the chamber in order to vaporize the metalorganic compound. The resonance is applied to the chamber until a metal doped carbon film is formed. The metalorganic compound is preferably selected from the group consisting of an organic salt of ruthenium, palladium, gold or platinum.

Studies of Metal-Metal Bonded Compounds in Catalysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berry, John F.

The overall goals of this research are (1) to define the fundamental coordination chemistry underlying successful catalytic transformations promoted by metal-metal bonded compounds, and (2) to explore new chemical transformations that occur at metal-metal bonded sites that could lead to the discovery of new catalytic processes. Transformations of interest include metal-promoted reactions of carbene, nitrene, or nitrido species to yield products with new C–C and C–N bonds, respectively. The most promising suite of transition metal catalysts for these transformations is the set of metal-metal bonded coordination compounds of Ru and Rh of the general formula M 2(ligand) 4, where Mmore » = Ru or Rh and ligand = a monoanionic, bridging ligand such as acetate. Development of new catalysts and improvement of catalytic conditions have been stymied by a general lack of knowledge about the nature of highly reactive intermediates in these reactions, the knowledge that is to be supplied by this work. Our three specific objectives for this year have been (A) to trap, isolate, and characterize new reactive intermediates of general relevance to catalysis, (B) to explore the electronic structure and reactivity of these unusual species, and how these two properties are interrelated, and (C) to use our obtained mechanistic knowledge to design new catalysts with a focus on Earth-abundant first-row transition metal compounds.« less

Fire extinguishant materials

NASA Technical Reports Server (NTRS)

Altman, R. L.; Mayer, L. A.; Ling, A. C. (Inventor)

1983-01-01

Fire extinguishant composition comprising a mixture of a finely divided aluminum compound and alkali metal, stannous or plumbous halide is provided. Aluminum compound may be aluminum hydroxide, alumina or boehmite but preferably it is an alkali metal dawsonite. The metal halide may be an alkali metal, e.g. potassium iodide, bromide or chloride or stannous or plumbous iodide, bromide or chloride. Potassium iodide is preferred.

Effects of Ga substitution on the structural and magnetic properties of half metallic Fe{sub 2}MnSi Heusler compound

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pedro, S. S., E-mail: sandrapedro@uerj.br; Caraballo Vivas, R. J.; Andrade, V. M.

2015-01-07

The so-called half-metallic magnets have been proposed as good candidates for spintronic applications due to the feature of exhibiting a hundred percent spin polarization at the Fermi level. Such materials follow the Slater-Pauling rule, which relates the magnetic moment with the valence electrons in the system. In this paper, we study the bulk polycrystalline half-metallic Fe{sub 2}MnSi Heusler compound replacing Si by Ga to determine how the Ga addition changes the magnetic, the structural, and the half-metal properties of this compound. The material does not follow the Slater-Pauling rule, probably due to a minor structural disorder degree in the system,more » but a linear dependence on the magnetic transition temperature with the valence electron number points to the half-metallic behavior of this compound.« less

Composition suitable for use as inert electrode having good electrical conductivity and mechanical properties

DOEpatents

Ray, S.P.; Rapp, R.A.

1984-06-12

An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metals or metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily. 8 figs.

Composition suitable for use as inert electrode having good electrical conductivity and mechanical properties

DOEpatents

Ray, Siba P.; Rapp, Robert A.

1984-01-01

An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metals or metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily.

Method of making composition suitable for use as inert electrode having good electrical conductivity and mechanical properties

DOEpatents

Ray, Siba P.; Rapp, Robert A.

1986-01-01

An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metals or metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily.

Method of making metal oxide ceramic powders by using a combustible amino acid compound

DOEpatents

Pederson, L.R.; Chick, L.A.; Exarhos, G.J.

1992-05-19

This invention is directed to the formation of homogeneous, aqueous precursor mixtures of at least one substantially soluble metal salt and a substantially soluble, combustible co-reactant compound, typically an amino acid. This produces, upon evaporation, a substantially homogeneous intermediate material having a total solids level which would support combustion. The homogeneous intermediate material essentially comprises highly dispersed or solvated metal constituents and the co-reactant compound. The intermediate material is quite flammable. A metal oxide powder results on ignition of the intermediate product which combusts same to produce the product powder.

Method of making metal oxide ceramic powders by using a combustible amino acid compound

DOEpatents

Pederson, Larry R.; Chick, Lawrence A.; Exarhos, Gregory J.

1992-01-01

This invention is directed to the formation of homogeneous, aqueous precursor mixtures of at least one substantially soluble metal salt and a substantially soluble, combustible co-reactant compound, typically an amino acid. This produces, upon evaporation, a substantially homogeneous intermediate material having a total solids level which would support combustion. The homogeneous intermediate material essentially comprises highly dispersed or solvated metal constituents and the co-reactant compound. The intermediate material is quite flammable. A metal oxide powder results on ignition of the intermediate product which combusts same to produce the product powder.

Too easily lead? Health effects of gasoline additives.

PubMed Central

Menkes, D B; Fawcett, J P

1997-01-01

Octane-enhancing constituents of gasoline pose a number of health hazards. This paper considers the relative risks of metallic (lead, manganese), aromatic (e.g., benzene), and oxygenated additives in both industrialized and developing countries. Technological advances, particularly in industrialized countries, have allowed the progressive removal of lead from gasoline and the increased control of exhaust emissions. The developing world, by contrast, has relatively lax environmental standards and faces serious public health problems from vehicle exhaust and the rapid increase in automobile use. Financial obstacles to the modernization of refineries and vehicle fleets compound this problem and the developing world continues to import large quantities of lead additives and other hazardous materials. Progress in decreasing environmental health problems depends both on the adoption of international public health standards as well as efforts to decrease dependence on the private automobile for urban transport. Images Figure 1. Figure 2. PMID:9171982

Jacks of metal/metalloid chelation trade in plants—an overview

PubMed Central

Anjum, Naser A.; Hasanuzzaman, Mirza; Hossain, Mohammad A.; Thangavel, Palaniswamy; Roychoudhury, Aryadeep; Gill, Sarvajeet S.; Rodrigo, Miguel A. Merlos; Adam, Vojtěch; Fujita, Masayuki; Kizek, Rene; Duarte, Armando C.; Pereira, Eduarda; Ahmad, Iqbal

2015-01-01

Varied environmental compartments including soils are being contaminated by a myriad toxic metal(loid)s (hereafter termed as “metal/s”) mainly through anthropogenic activities. These metals may contaminate food chain and bring irreparable consequences in human. Plant-based approach (phytoremediation) stands second to none among bioremediation technologies meant for sustainable cleanup of soils/sites with metal-contamination. In turn, the capacity of plants to tolerate potential consequences caused by the extracted/accumulated metals decides the effectiveness and success of phytoremediation system. Chelation is among the potential mechanisms that largely govern metal-tolerance in plant cells by maintaining low concentrations of free metals in cytoplasm. Metal-chelation can be performed by compounds of both thiol origin (such as GSH, glutathione; PCs, phytochelatins; MTs, metallothioneins) and non-thiol origin (such as histidine, nicotianamine, organic acids). This paper presents an appraisal of recent reports on both thiol and non-thiol compounds in an effort to shed light on the significance of these compounds in plant-metal tolerance, as well as to provide scientific clues for the advancement of metal-phytoextraction strategies. PMID:25883598

Alkali metal intercalates of molybdenum disulfide.

NASA Technical Reports Server (NTRS)

Somoano, R. B.; Hadek, V.; Rembaum, A.

1973-01-01

Study of some of the physicochemical properties of compounds obtained by subjecting natural molybdenite and single crystals of molybdenum disulfide grown by chemical vapor transport to intercalation with the alkali group of metals (Li, Na, K, Rb, and Cs) by means of the liquid ammonia technique. Reported data and results include: (1) the intercalation of the entire alkali metal group, (2) stoichiometries and X-ray data on all of the compounds, and (3) superconductivity data for all the intercalation compounds.

LIQUID METAL COMPOSITIONS CONTAINING URANIUM

DOEpatents

Teitel, R.J.

1959-04-21

Liquid metal compositions containing a solid uranium compound dispersed therein is described. Uranium combines with tin to form the intermetallic compound USn/sub 3/. It has been found that this compound may be incorporated into a liquid bath containing bismuth and lead-bismuth components, if a relatively small percentage of tin is also included in the bath. The composition has a low thermal neutron cross section which makes it suitable for use in a liquid metal fueled nuclear reactor.

Impact of metal-induced degradation on the determination of pharmaceutical compound purity and a strategy for mitigation.

PubMed

Dotterer, Sally K; Forbes, Robert A; Hammill, Cynthia L

2011-04-05

Case studies are presented demonstrating how exposure to traces of transition metals such as copper and/or iron during sample preparation or analysis can impact the accuracy of purity analysis of pharmaceuticals. Some compounds, such as phenols and indoles, react with metals in the presence of oxygen to produce metal-induced oxidative decomposition products. Compounds susceptible to metal-induced decomposition can degrade following preparation for purity analysis leading to falsely high impurity results. Our work has shown even metals at levels below 0.1 ppm can negatively impact susceptible compounds. Falsely low results are also possible when the impurities themselves react with metals and degrade prior to analysis. Traces of metals in the HPLC mobile phase can lead to chromatographic artifacts, affecting the reproducibility of purity results. To understand and mitigate the impact of metal induced decomposition, a proactive strategy is presented. The pharmaceutical would first be tested for reactivity with specific transition metals in the sample solvent/diluents and in the HPLC mobile phase. If found to be reactive, alternative sample diluents and/or mobile phases with less reactive solvents or addition of a metal chelator would be explored. If unsuccessful, glassware cleaning or sample solution refrigeration could be investigated. By employing this strategy during method development, robust purity methods would be delivered to the quality control laboratories, preventing future problems from potential sporadic contamination of glassware with metals. Copyright © 2010 Elsevier B.V. All rights reserved.

Hydrogen Peroxide, Signaling in Disguise during Metal Phytotoxicity

PubMed Central

Cuypers, Ann; Hendrix, Sophie; Amaral dos Reis, Rafaela; De Smet, Stefanie; Deckers, Jana; Gielen, Heidi; Jozefczak, Marijke; Loix, Christophe; Vercampt, Hanne; Vangronsveld, Jaco; Keunen, Els

2016-01-01

Plants exposed to excess metals are challenged by an increased generation of reactive oxygen species (ROS) such as superoxide (O2•-), hydrogen peroxide (H2O2) and the hydroxyl radical (•OH). The mechanisms underlying this oxidative challenge are often dependent on metal-specific properties and might play a role in stress perception, signaling and acclimation. Although ROS were initially considered as toxic compounds causing damage to various cellular structures, their role as signaling molecules became a topic of intense research over the last decade. Hydrogen peroxide in particular is important in signaling because of its relatively low toxicity, long lifespan and its ability to cross cellular membranes. The delicate balance between its production and scavenging by a plethora of enzymatic and metabolic antioxidants is crucial in the onset of diverse signaling cascades that finally lead to plant acclimation to metal stress. In this review, our current knowledge on the dual role of ROS in metal-exposed plants is presented. Evidence for a relationship between H2O2 and plant metal tolerance is provided. Furthermore, emphasis is put on recent advances in understanding cellular damage and downstream signaling responses as a result of metal-induced H2O2 production. Finally, special attention is paid to the interaction between H2O2 and other signaling components such as transcription factors, mitogen-activated protein kinases, phytohormones and regulating systems (e.g. microRNAs). These responses potentially underlie metal-induced senescence in plants. Elucidating the signaling network activated during metal stress is a pivotal step to make progress in applied technologies like phytoremediation of polluted soils. PMID:27199999

Polymerization catalysts containing electron-withdrawing amide ligands

DOEpatents

Watkin, John G.; Click, Damon R.

2002-01-01

The present invention describes methods of making a series of amine-containing organic compounds which are used as ligands for group 3-10 and lanthanide metal compounds. The ligands have electron-withdrawing groups bonded to them. The metal compounds, when combined with a cocatalyst, are catalysts for the polymerization of olefins.

Novel Route to Transition Metal Isothiocyanate Complexes Using Metal Powders and Thiourea

NASA Technical Reports Server (NTRS)

Harris, Jerry D.; Eckles, William E.; Hepp, Aloysius F.; Duraj, Stan A.; Hehemann, David G.; Fanwick, Phillip E.; Richardson, John

2003-01-01

A new synthetic route to isothiocyanate-containing materials is presented. Eight isothiocyanate- 4-methylpyridine (y-picoline) compounds were prepared by refluxing metal powders (Mn, Fe, Co, Ni, and Cu) with thiourea in y-picoline. With the exception of compound 5,prepared with Co, the isothiocyanate ligand was generated in situ by the isomerization of thiourea to NH4+SCN- at reflux temperatures. The complexes were characterized by x-ray crystallography. Compounds 1,2, and 8 are the first isothiocyanate- 4-methylpyridine anionic compounds ever prepared and structurally characterized. Compounds 1 and 2 are isostructural with four equatorially bound isothiocyanate ligands and two axially bound y-picoline molecules. Compound 8 is a five-coordinate copper(II) molecule with a distorted square-pyramidal geometry. Coordinated picoline and two isothiocyanates form the basal plane and the remaining isothiocyanate is bound at the apex. Structural data are presented for all compounds.

Tuning reactivity of diphenylpropynone derivatives with metal-associated amyloid-β species via structural modifications.

PubMed

Liu, Yuzhong; Kochi, Akiko; Pithadia, Amit S; Lee, Sanghyun; Nam, Younwoo; Beck, Michael W; He, Xiaoming; Lee, Dongkuk; Lim, Mi Hee

2013-07-15

A diphenylpropynone derivative, DPP2, has been recently demonstrated to target metal-associated amyloid-β (metal-Aβ) species implicated in Alzheimer's disease (AD). DPP2 was shown to interact with metal-Aβ species and subsequently control Aβ aggregation (reactivity) in vitro; however, its cytotoxicity has limited further biological applications. In order to improve reactivity toward Aβ species and lower cytotoxicity, along with gaining an understanding of a structure-reactivity-cytotoxicity relationship, we designed, prepared, and characterized a series of small molecules (C1/C2, P1/P2, and PA1/PA2) as structurally modified DPP2 analogues. A similar metal binding site to that of DPP2 was contained in these compounds while their structures were varied to afford different interactions and reactivities with metal ions, Aβ species, and metal-Aβ species. Distinct reactivities of our chemical family toward in vitro Aβ aggregation in the absence and presence of metal ions were observed. Among our chemical series, the compound (C2) with a relatively rigid backbone and a dimethylamino group was observed to noticeably regulate both metal-free and metal-mediated Aβ aggregation to different extents. Using our compounds, cell viability was significantly improved, compared to that with DPP2. Lastly, modifications on the DPP framework maintained the structural properties for potential blood-brain barrier (BBB) permeability. Overall, our studies demonstrated that structural variations adjacent to the metal binding site of DPP2 could govern different metal binding properties, interactions with Aβ and metal-Aβ species, reactivity toward metal-free and metal-induced Aβ aggregation, and cytotoxicity of the compounds, establishing a structure-reactivity-cytotoxicity relationship. This information could help gain insight into structural optimization for developing nontoxic chemical reagents toward targeting metal-Aβ species and modulating their reactivity in biological systems.

Fundamental Studies and Isolation Strategies for Metal Compound Nanoclusters

DTIC Science & Technology

2009-02-28

probe nanocluster structure, bonding and stability, metal oxide, carbide and silicide clusters with up to 50 atoms were investigated with mass...transition metal compounds (carbides, oxides, silicides ) that are expected to have high stability, an essential property for their isolation...Metal carbide, oxide and silicide nanoclusters are studied in the size range from a few up to about 300 atoms. New infrared laser spectroscopy

Complete Characterization of trans- Co(en)2Cl2[3 Fe(ox)3[.4-1/2H2O: An Extended Undergraduate Project Involving an Unknown Metal Complex.

ERIC Educational Resources Information Center

Bull, Graham S.; Searle, Graeme H.

1986-01-01

Discusses the need for student experiments involving the complete characterization of "unknown" inorganic compounds. Describes a project employing a complex metal compound. The compound contains six different components in both inert and labile complexions. Outlines the complete procedure and the preparation of the unknown compound. (TW)

PERIODIC CLASSIFICATION AND THE PROUST LAW (in French)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rinck, E.; Feschotte, P.

1962-04-01

Progress realized in the knowledge of the solid state has permitted the identification of numerous crystalline phases whose composition was not defined in the meaning of the Proust law. Its rigorous validity has nevertheless served as a beginning for atomic theory; it continues to be utilized in the measurement of atomic weights and remains valid for the vast region of organic chemistry. The investigation of the limits of the validity of the Proust law leads to some peculiarities of the metallic state which are closely connected to the periodic classification of elements. A new arrangement of the periodic table, permittingmore » for the first time the integration of the rare earths and giving to hydrogen a very special place, takes into consideration a distinction between true metals and earth metals. This distinction is imposed by the fact that the Proust law, valid for compounds between metalloids and earth metals, is not always followed when these same metalloids unite with true metals. Finally. this law loses all significance in alloys between true metals. The exceptions to this rule are explained by the specialization of chemical properties which is shown when one passes from short periods to long periods, hydrogen and the metals with short period being considered as undifferentiated elements. The usage of a point of view borrowed from embryology permits, thus, the chemical and even the physical properties of these elements to be better connected. (tr-auth)« less

Physico-chemical study of some areas of fundamental significance to biophysics. Annual report, 1975--1976. [Chemistry Dept. , Louisiana State University, Baton Rouge

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGlynn, S.P.

1976-05-15

Lists of titles published, symposia attended, laboratory guests, departing personnel, and equipment purchased are presented in the first part of this report. It is to be emphasized that completed work already published is mentioned only by title. Reports are provided for research recently completed or in progress in the following areas: Rydberg spectroscopy, intermediate-coupling model for linear molecules, atomic correlation lines, electronic structure of dicarbonyl compounds, absorption and emission characteristics of highly polar aromatics, valence-bond description of metal--anion interaction, and matrix elements of mono-excited Slater determinants constructed from axial spin-orbitals. (RWR)

WELDING PROCESS

DOEpatents

Zambrow, J.; Hausner, H.

1957-09-24

A method of joining metal parts for the preparation of relatively long, thin fuel element cores of uranium or alloys thereof for nuclear reactors is described. The process includes the steps of cleaning the surfaces to be jointed, placing the sunfaces together, and providing between and in contact with them, a layer of a compound in finely divided form that is decomposable to metal by heat. The fuel element members are then heated at the contact zone and maintained under pressure during the heating to decompose the compound to metal and sinter the members and reduced metal together producing a weld. The preferred class of decomposable compounds are the metal hydrides such as uranium hydride, which release hydrogen thus providing a reducing atmosphere in the vicinity of the welding operation.

Inert electrode containing metal oxides, copper and noble metal

DOEpatents

Ray, Siba P.; Woods, Robert W.; Dawless, Robert K.; Hosler, Robert B.

2001-01-01

A cermet composite material is made by treating at an elevated temperature a mixture comprising a compound of iron and a compound of at least one other metal, together with an alloy or mixture of copper and a noble metal. The alloy or mixture preferably comprises particles having an interior portion containing more copper than noble metal and an exterior portion containing more noble metal than copper. The noble metal is preferably silver. The cermet composite material preferably includes alloy phase portions and a ceramic phase portion. At least part of the ceramic phase portion preferably has a spinel structure.

Inert electrode containing metal oxides, copper and noble metal

DOEpatents

Ray, Siba P.; Woods, Robert W.; Dawless, Robert K.; Hosler, Robert B.

2000-01-01

A cermet composite material is made by treating at an elevated temperature a mixture comprising a compound of iron and a compound of at least one other metal, together with an alloy or mixture of copper and a noble metal. The alloy or mixture preferably comprises particles having an interior portion containing more copper than noble metal and an exterior portion containing more noble metal than copper. The noble metal is preferably silver. The cermet composite material preferably includes alloy phase portions and a ceramic phase portion. At least part of the ceramic phase portion preferably has a spinel structure.

Method of making composition suitable for use as inert electrode having good electrical conductivity and mechanical properties

DOEpatents

Ray, S.P.; Rapp, R.A.

1986-04-22

An improved inert electrode composition is suitable for use as an inert electrode in the production of metals such as aluminum by the electrolytic reduction of metal oxide or metal salt dissolved in a molten salt bath. The composition comprises one or more metals or metal alloys and metal compounds which may include oxides of the metals comprising the alloy. The alloy and metal compounds are interwoven in a network which provides improved electrical conductivity and mechanical strength while preserving the level of chemical inertness necessary for such an electrode to function satisfactorily. 8 figs.

Review of the Toxicity of the Metallic Compounds Proposed for Use in the New Green Missile Formulation

NASA Technical Reports Server (NTRS)

Major, Michael A.

2000-01-01

In an effort to modernize and minimize hazards posed by the toxic components of missile propellant, the USACHPPM has been tasked to provide a comparison of the toxicity of compounds currently in use as missile propellants and the suite of compounds proposed to replace them. This report deals with the portion of this work concerning the toxicity of the organometallic compounds used in these formulations. Toxicity assessments of the organic compounds used in these formulations are published elsewhere. In general, toxicity data were available for all the metal compounds of concern or for closely related compounds that can serve as surrogates for the assessment of toxicity. We have high confidence in the reliability of these comparisons. This report is organized by element to provide the reader with an in-depth assessment with a minimum of redundancy. The narrative will first describe general concepts about the toxicity of each metal and then provide a summary of the toxicological information available for the specific compound.

Process for reducing aromatic compounds in ethylenediamine with calcium

DOEpatents

Benkeser, Robert A.; Laugal, James A.; Rappa, Angela

1985-01-01

Olefins are produced by containing an organic compound having at least one benzene ring with ethylenediamine and calcium metal, the calcium metal being used in large excess or alternatively in conjunction with an inert abrasive particulate substance. Substantially all of the organic compounds are converted to corresponding cyclic olefins, largely mono-olefins.

Process for reducing aromatic compounds in ethylenediamine with calcium

DOEpatents

Benkeser, R.A.; Laugal, J.A.; Rappa, A.

1985-08-06

Olefins are produced by containing an organic compound having at least one benzene ring with ethylenediamine and calcium metal, the calcium metal being used in large excess or alternatively in conjunction with an inert abrasive particulate substance. Substantially all of the organic compounds are converted to corresponding cyclic olefins, largely mono-olefins.

Layered transition metal carboxylates: synthesis, structural aspects and observation of multi-step magnetic transition through phase diagram.

PubMed

Sen, Rupam; Mal, Dasarath; Lopes, Armandina M L; Brandão, Paula; Araújo, João P; Lin, Zhi

2013-10-01

Two new layered transition metal carboxylate frameworks, [Co3(L)2(H2O)6]·2H2O () and [Ni3(L)2(H2O)6]·2H2O () (L = tartronate anion or hydroxymalonic acid), have been synthesized and characterized by X-ray single crystal analysis. Both compounds have similar 2D structures. In both compounds there are two types of metal centers where one center is doubly bridged by the alkoxy oxygen atoms through μ2-O bridging to form a 1D infinite chain parallel to the crystallographic b-axis with the corners shared between the metal polyhedra. Magnetic susceptibility measurements revealed the existence of antiferromagnetic short range correlations between Co(Ni) intra-chain metal centers (with exchange constants JCo = -22.6 and JNi = -35.4 K). At low temperatures, long range order is observed in both compounds at Néel temperatures of 11 (for ) and 16 (for ) K, revealing that other exchange interactions, rather than the intra-chain ones, play a role in these systems. Whereas compound has an antiferromagnetic ground state, compound exhibits a ferromagnetic component, probably due to spin canting. Isothermal magnetization data unveiled a rich phase diagram with three metamagnetic phase transitions below 8 K in compound .

Adsorptive desulfurization with metal-organic frameworks: A density functional theory investigation

NASA Astrophysics Data System (ADS)

Chen, Zhiping; Ling, Lixia; Wang, Baojun; Fan, Huiling; Shangguan, Ju; Mi, Jie

2016-11-01

The contribution of each fragment of metal-organic frameworks (MOFs) to the adsorption of sulfur compounds were investigated using density functional theory (DFT). The involved sulfur compounds are dimethyl sulfide (CH3SCH3), ethyl mercaptan (CH3CH2SH) and hydrogen sulfide (H2S). MOFs with different organic ligands (NH2-BDC, BDC and NDC), metal centers structures (M, M-M and M3O) and metal ions (Zn, Cu and Fe) were used to study their effects on sulfur species adsorption. The results revealed that, MOFs with coordinatively unsaturated sites (CUS) have the strongest binding strength with sulfur compounds, MOFs with NH2-BDC substituent group ligand comes second, followed by that with saturated metal center, and the organic ligands without substituent group has the weakest adsorption strength. Moreover, it was also found that, among different metal ions (Fe, Zn and Cu), MOFs with unsaturated Fe has the strongest adsorption strength for sulfur compounds. These results are consistent with our previous experimental observations, and therefore provide insights on the better design of MOFs for desulfurization application.

Metallic elements in fossil fuel combustion products: amounts and form of emissions and evaluation of carcinogenicity and mutagenicity.

PubMed

Vouk, V B; Piver, W T

1983-01-01

Metallic elements contained in coal, oil and gasoline are mobilized by combustion processes and may be emitted into the atmosphere, mainly as components of submicron particles. The information about the amounts, composition and form of metal compounds is reviewed for some fuels and combustion processes. Since metal compounds are always contained in urban air pollutants, they have to be considered whenever an evaluation of biological impact of air pollutants is made. The value of currently used bioassays for the evaluation of the role of trace metal compounds, either as major biologically active components or as modifiers of biological effects of organic compounds is assessed. The whole animal bioassays for carcinogenicity do not seem to be an appropriate approach. They are costly, time-consuming and not easily amenable to the testing of complex mixtures. Some problems related to the application and interpretation of short-term bioassays are considered, and the usefulness of such bioassays for the evaluation of trace metal components contained in complex air pollution mixtures is examined.

Metallic elements in fossil fuel combustion products: amounts and form of emissions and evaluation of carcinogenicity and mutagenicity.

PubMed Central

Vouk, V B; Piver, W T

1983-01-01

Metallic elements contained in coal, oil and gasoline are mobilized by combustion processes and may be emitted into the atmosphere, mainly as components of submicron particles. The information about the amounts, composition and form of metal compounds is reviewed for some fuels and combustion processes. Since metal compounds are always contained in urban air pollutants, they have to be considered whenever an evaluation of biological impact of air pollutants is made. The value of currently used bioassays for the evaluation of the role of trace metal compounds, either as major biologically active components or as modifiers of biological effects of organic compounds is assessed. The whole animal bioassays for carcinogenicity do not seem to be an appropriate approach. They are costly, time-consuming and not easily amenable to the testing of complex mixtures. Some problems related to the application and interpretation of short-term bioassays are considered, and the usefulness of such bioassays for the evaluation of trace metal components contained in complex air pollution mixtures is examined. PMID:6337825

Experimental formation enthalpies for intermetallic phases and other inorganic compounds

PubMed Central

Kim, George; Meschel, S. V.; Nash, Philip; Chen, Wei

2017-01-01

The standard enthalpy of formation of a compound is the energy associated with the reaction to form the compound from its component elements. The standard enthalpy of formation is a fundamental thermodynamic property that determines its phase stability, which can be coupled with other thermodynamic data to calculate phase diagrams. Calorimetry provides the only direct method by which the standard enthalpy of formation is experimentally measured. However, the measurement is often a time and energy intensive process. We present a dataset of enthalpies of formation measured by high-temperature calorimetry. The phases measured in this dataset include intermetallic compounds with transition metal and rare-earth elements, metal borides, metal carbides, and metallic silicides. These measurements were collected from over 50 years of calorimetric experiments. The dataset contains 1,276 entries on experimental enthalpy of formation values and structural information. Most of the entries are for binary compounds but ternary and quaternary compounds are being added as they become available. The dataset also contains predictions of enthalpy of formation from first-principles calculations for comparison. PMID:29064466

Process for production of a borohydride compound

DOEpatents

Allen, Nathan Tait; Butterick, III, Robert; Chin, Arthur Achhing; Millar, Dean Michael; Molzahn, David Craig

2014-08-19

A process for production of a borohydride compound M(BH.sub.4).sub.y. The process has three steps. The first step combines a compound of formula (R.sup.1O).sub.yM with aluminum, hydrogen and a metallic catalyst containing at least one metal selected from the group consisting of titanium, zirconium, hafnium, niobium, vanadium, tantalum and iron to produce a compound of formula M(AlH.sub.3OR.sup.1).sub.y, wherein R.sup.1 is phenyl or phenyl substituted by at least one alkyl or alkoxy group; M is an alkali metal, Be or Mg; and y is one or two; wherein the catalyst is present at a level of at least 200 ppm based on weight of aluminum. The second step combines the compound of formula M(AlH.sub.3OR.sup.1).sub.y with a borate, boroxine or borazine compound to produce M(BH.sub.4).sub.y and a byproduct mixture containing alkali metal and aluminum aryloxides. The third step separates M(BH.sub.4).sub.y from the byproduct mixture.

First-principles study of half-metallic properties in RbCaNZ (Z = O, S, and Se) quaternary Heusler compounds

NASA Astrophysics Data System (ADS)

Rezaei, S.; Ahmadian, F.

2018-06-01

On the basis of first principles calculations, the electronic structures and magnetic properties of quaternary Heusler alloys RbCaNZ (Z = O, S, and Se) were studied. The negative formation energies indicated that all these compounds were thermodynamically stable and thus may be experimentally synthesized at appropriate conditions in the future. The results showed that YI structure was the most favorable configuration among the three possible structures. All compounds were found to be half-metallic ferromagnets. The characteristic of energy bands and origin of half-metallicity were also verified. The total magnetic moments of RbCaNZ (Z = O, S, and Se) compounds were obtained 2μB per formula unit, which were in an agreement with Slater-Pauling rule (Mtot = 12 - Ztot). Half-metallicity was preserved at ranges of 5.06-8.36 Å, 5.96-8.81 Å, and 6.13-8.73 Å for RbCaNO, RbCaNS, and RbCaNSe compounds, respectively, which show that these quaternary Heusler compounds may be potential candidates in spintronic applications.

Heavy Metals in ToxCast: Relevance to Food Safety (SOT) ...

EPA Pesticide Factsheets

Human exposure to heavy metals occurs through food contamination due to industrial processes, vehicle emissions and farming methods. Specific toxicity endpoints have been associated with metal exposures, e.g. lead and neurotoxicity; however, numerous varieties of heavy metals have not been systematically examined for potential toxicities. We describe results from testing a large set of heavy metal-containing compounds in extensive suites of in vitro assays to suggest possible molecular initiating events in toxicity pathways. A broad definition of heavy metals that includes As, Se and organometallics or inorganic salts containing metals in Group III or higher (MW > 40) was used to identify 75 different compounds tested in the EPA’s ToxCast assays encompassing biochemical, cellular and model organism assays. These 75, plus an additional 100 metal-containing compounds, were tested in Tox21 quantitative high-throughput screening (qHTS) assays covering nuclear receptor and stress pathways. Known activities were confirmed such as activation of stress pathways and nuclear receptors (RXR, PPARg) as well as overt cytotoxicity. Specifically, organotin and organomercury were among the most potent of over 8K chemicals tested. The HTS results support known toxicities, including promiscuous GPCR activity for mercury compounds consistent with the neuropsychiatric effects seen in mercury poisoning (Mad Hatter’s Syndrome). As such, HTS approaches provide an efficient method

THE DIFFERENTIAL THERMAL ANALYSIS OF CYANO-TRANSITION METAL COMPLEXES

DTIC Science & Technology

COMPOUNDS, CHROMATES, COBALT COMPOUNDS, CYANIDES, CYANOGEN, DYES, FERRATES , GASES, HEAT, HYDROXIDES, LITHIUM COMPOUNDS, MOLYBDATES, NICKELATES, NITRATES...OXIDATION REDUCTION REACTIONS, POTASSIUM COMPOUNDS, SILVER COMPOUNDS, SODIUM COMPOUNDS, VANADATES

Investigation of half-metallic ferromagnetism in Heusler compounds Co2VZ (Z = Ga, Ge, As, Se)

NASA Astrophysics Data System (ADS)

Han, Jiajia; Wang, Zhengwei; Xu, Weiwei; Wang, Cuiping; Liu, Xingjun

2017-11-01

The electronic structures and magnetic properties of 3d transition metal-based full Heusler compounds Co2VZ (Z = Ga, Ge, As, Se) are investigated using the projector augmented wave (PAW) pseudopotential method. By considering the strong localization of Co 3d-states and V 3d-states at the Fermi level, these Co2VZ (Z = Ga, Ge, As, Se) compounds were treated in the framework of the generalized gradient approximation (GGA)+U method, and the results from the conventional GGA method are presented for comparison. The results that were obtained from the density of states with the GGA+U and GGA methods show that the Co2VGa compound is a half-metallic ferromagnet. For the Co2VGe and Co2VAs compounds, the GGA+U method predicts that these two compounds are half-metallic ferromagnetic by shifting the Fermi level to a lower value with respect to the gap in the minority states, when compared to the conventional GGA method. The energy gaps are determined to be 0.283 eV and 0.425 eV, respectively. However, these results show that the density of states of the Co2VSe compound has a metallic character, although the 3d states were corrected when using the GGA+U method. We found that the characteristic of half-metallic ferromagnetism is attributed to the interaction between the V 3d-states other than Co 3d-states. The calculated total magnetic moments are 2.046 μB, 3.054 μB and 4.012 μB respectively for the Co2VZ (Z = Ga, Ge, As) compounds with the GGA+U method. The relationship between total spin magnetic moment per formula unit and total number of valence electrons of these Heusler compounds is in agreement with the Slater-Pauling rule.

Organic Superconductor, Made without Metals.

ERIC Educational Resources Information Center

Science News, 1980

1980-01-01

The discovery of a superconducting organic compound is reported. The compound, (TMTSF)-2, has no metal in its composition, and the author believes that it is the precursor of a family of superconducting organics. (Author/SA)

X-ray magnetic circular dichroism in d and f ferromagnetic materials: recent theoretical progress. Part II (Review Article)

NASA Astrophysics Data System (ADS)

Antonov, V. N.; Shpak, A. P.; Yaresko, A. N.

2008-02-01

The present state of theoretical understanding of the x-ray magnetic circular dichroism (XMCD) of 4f and 5f compounds is reviewed. Energy band theory based upon the local spin-density approximation (LSDA) describes the XMCD spectra of transition metal compounds with high accuracy. However, the LSDA does not suffice for lanthanide compounds which have a correlated 4f shell. A satisfactory description of the XMCD spectra could be obtained by using a generalization of the LSDA, in which explicitly f electron Coulomb correlations are taken into account (LSDA +U approach). As examples of this group we consider the compound GdN. We also consider uranium 5f compounds. In those compounds where the 5f electrons are rather delocalized, the LSDA describes the XMCD spectra reasonably well. As an example of this group we consider UFe2. Particular differences occur for uranium compounds in which the 5f electrons are neither delocalized nor localized, but more or less semilocalized. Typical examples are UXAl (X =Co, Rh, and Pt), and UX (X =S, Se, Te). However, the semilocalized 5f's are not inert, but their interaction with conduction electrons plays an important role. We also consider the electronic structure and XMCD spectra of the heavy-fermion compounds UPt3, URu2Si2, UPd2Al3, UNi2Al3, and UBe13, where the degree of the 5f localization is increased in comparison with other uranium compounds. The electronic structure and XMCD spectra of UGe2 which possesses simultaneously ferromagnetism and superconductivity also presented. Recently achieved improvements for describing 5f compounds are discussed.

Catalysts for the hydrodenitrogenation of organic materials and process for the preparation of the catalysts

DOEpatents

Laine, R.M.; Hirschon, A.S.; Wilson, R.B. Jr.

1987-12-29

A process is described for the preparation of a multimetallic catalyst for the hydrodenitrogenation of an organic feedstock, which process comprises: (a) forming a precatalyst itself comprising: (1) a first metal compound selected from compounds of nickel, cobalt or mixtures thereof; (2) a second metal compound selected from compounds of chromium, molybdenum, tungsten, or mixtures thereof; and (3) an inorganic support; (b) heating the precatalyst of step (a) with a source of sulfide in a first non-oxidizing gas at a temperature and for a time effective to presulfide the precatalyst; (c) adding in a second non-oxidizing gas to the sulfided precatalyst of step (b) an organometallic transition metal moiety selected from compounds of iridium, rhodium, iron, ruthenium, tungsten or mixtures thereof for a time and at a temperature effective to chemically combine the metal components; and (d) optionally heating the chemically combined catalyst of step (b) in vacuum at a temperature and for a time effective to remove residual volatile organic materials. 12 figs.

Methylocystis strain SB2 materials and methods

DOEpatents

Semrau, Jeremy D; Gallagher, Warren; Yoon, Sukhwan; Im, Jeongdae; DiSpririto, Alan A; Lee, Sung-Woo; Hartsel, Scott; McEllistrem, Marcus T

2014-01-14

The present disclosures provides isolated or purified compounds, each of which bind to a metal atom. Generally, the compounds are small in size (e.g., molecular weight of less than about 1 kDa) and peptidic in nature, inasmuch as the compounds comprise amino acids. In some embodiments, the compound comprises a structure of Formula I; M.sub.1-P.sub.1-M.sub.2-P.sub.2 wherein each of P.sub.1 and P.sub.2 is a peptide comprising at least two amino acids, M.sub.1 is a first metal binding moiety comprising a substituted imidazolone ring, M.sub.2 is a second metal binding moiety comprising a substituted oxazolone ring, and wherein M.sub.1 and M.sub.2 bind to a single metal atom. Also provided are related complexes, conjugates, cells which synthesize the compounds of the present disclosures, substantially homogenous cultures thereof, kits and compositions, and methods of making or using the materials of the present disclosures.

Electronic structure of semiconducting alkali-metal silicides and germanides

NASA Astrophysics Data System (ADS)

Tegze, M.; Hafner, J.

1989-11-01

We present self-consistent linearized-muffin-tin-orbital calculations of the electronic structure of three alkali-metal germanides and silicides (KGe, NaGe, and NaSi). Like the alkali-metal-lead compounds investigated in our earlier work [M. Tegze and J. Hafner, Phys. Rev. B 39, 8263 (1989)] the Ge and Si compounds of the alkali metals form complex structures based on the packing of tetrahedral Ge4 and Si4 clusters. Our calculations show that all three compounds are narrow-gap semiconductors. The width of the energy gap depends on two main factors: the ratio of the intracluster to the intercluster interactions between the group-IV elements (which increases from Pb to Si) and the strength of the interactions between the alkali-metal atoms (which varies with the size ratio).

Methods of forming boron nitride

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trowbridge, Tammy L; Wertsching, Alan K; Pinhero, Patrick J

A method of forming a boron nitride. The method comprises contacting a metal article with a monomeric boron-nitrogen compound and converting the monomeric boron-nitrogen compound to a boron nitride. The boron nitride is formed on the same or a different metal article. The monomeric boron-nitrogen compound is borazine, cycloborazane, trimethylcycloborazane, polyborazylene, B-vinylborazine, poly(B-vinylborazine), or combinations thereof. The monomeric boron-nitrogen compound is polymerized to form the boron nitride by exposure to a temperature greater than approximately 100.degree. C. The boron nitride is amorphous boron nitride, hexagonal boron nitride, rhombohedral boron nitride, turbostratic boron nitride, wurzite boron nitride, combinations thereof, or boronmore » nitride and carbon. A method of conditioning a ballistic weapon and a metal article coated with the monomeric boron-nitrogen compound are also disclosed.« less

Ni/metal hydride secondary element

DOEpatents

Bauerlein, Peter

2005-04-19

A Ni/metal hydride secondary element having a positive nickel hydroxide electrode, a negative electrode having a hydrogen storage alloy, and an alkaline electrolyte, the positive electrode, provided with a three-dimensional metallic conductive structure, also contains an aluminum compound which is soluble in the electrolyte, in addition to nickel hydroxide and cobalt oxide. The aluminum compound is aluminum hydroxide and/or aluminum oxide, and the mass of the aluminum compound which is present in the positive bulk material mixture is 0.1 to 2% by weight relative to the mass of the nickel hydroxide which is present. In combination with aluminum hydroxide or aluminum oxide, the positive electrode further contains lanthanoid oxidic compounds Y.sub.2 O.sub.3, La.sub.2 O.sub.3 and Ca(OH).sub.2, as well as mixtures of these compounds.

Method for fixating sludges and soils contaminated with mercury and other heavy metals

DOEpatents

Broderick, Thomas E.; Roth, Rachel L.; Carlson, Allan L.

2005-06-28

The invention relates to a method, composition and apparatus for stabilizing mercury and other heavy metals present in a particulate material such that the metals will not leach from the particulate material. The method generally involves the application of a metal reagent, a sulfur-containing compound, and the addition of oxygen to the particulate material, either through agitation, sparging or the addition of an oxygen-containing compound.

Oxidized film structure and method of making epitaxial metal oxide structure

DOEpatents

Gan, Shupan [Richland, WA; Liang, Yong [Richland, WA

2003-02-25

A stable oxidized structure and an improved method of making such a structure, including an improved method of making an interfacial template for growing a crystalline metal oxide structure, are disclosed. The improved method comprises the steps of providing a substrate with a clean surface and depositing a metal on the surface at a high temperature under a vacuum to form a metal-substrate compound layer on the surface with a thickness of less than one monolayer. The compound layer is then oxidized by exposing the compound layer to essentially oxygen at a low partial pressure and low temperature. The method may further comprise the step of annealing the surface while under a vacuum to further stabilize the oxidized film structure. A crystalline metal oxide structure may be subsequently epitaxially grown by using the oxidized film structure as an interfacial template and depositing on the interfacial template at least one layer of a crystalline metal oxide.

Method and apparatus for hydrogen production from water

NASA Technical Reports Server (NTRS)

Muradov, Nazim Z. (Inventor)

2012-01-01

A method, apparatuses and chemical compositions are provided for producing high purity hydrogen from water. Metals or alloys capable of reacting with water and producing hydrogen in aqueous solutions at ambient conditions are reacted with one or more inorganic hydrides capable of releasing hydrogen in aqueous solutions at ambient conditions, one or more transition metal compounds are used to catalyze the reaction and, optionally, one or more alkali metal-based compounds. The metal or alloy is preferably aluminum. The inorganic hydride is from a family of complex inorganic hydrides; most preferably, NaBH.sub.4. The transition metal catalyst is from the groups VIII and IB; preferably, Cu and Fe. The alkali metal-based compounds are preferably NaOH, KOH, and the like. Hydrogen generated has a purity of at least 99.99 vol. % (dry basis), and is used without further purification in all types of fuel cells, including the polymer electrolyte membrane (PEM) fuel cell.

Non-hydrolytic metal oxide films for perovskite halide overcoating and stabilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinson, Alex B.; Kim, In Soo

A method of protecting a perovskite halide film from moisture and temperature includes positioning the perovskite halide film in a chamber. The chamber is maintained at a temperature of less than 200 degrees Celsius. An organo-metal compound is inserted into the chamber. A non-hydrolytic oxygen source is subsequently inserted into the chamber. The inserting of the organo-metal compound and subsequent inserting of the non-hydrolytic oxygen source into the chamber is repeated for a predetermined number of cycles. The non-hydrolytic oxygen source and the organo-metal compound interact in the chamber to deposit a non-hydrolytic metal oxide film on perovskite halide film.more » The non-hydrolytic metal oxide film protects the perovskite halide film from relative humidity of greater than 35% and a temperature of greater than 150 degrees Celsius, respectively.« less

The electronic, structural and magnetic properties of Heusler compounds ZrCrCoZ(Z=B, Al, Ga, In): A first-principles study

NASA Astrophysics Data System (ADS)

Guo, R. K.; Liu, G. D.; Lin, T. T.; Wang, W.; Wang, L. Y.; Dai, X. F.

2018-02-01

It is predicted that the ZrCrCoZ(Z=B, Al, Ga, In) compounds with LiMnPbSn-type structure are half-metallic ferrimagnets with a large half-metallic gap by the first-principles calculations. The half-metallicity of the ZrCrCoZ(Z=B, Al, Ga, In) compounds are quite robust to the axial and uniaxial strain. The total magnetic moments in per unit cell are 4 μB for the ZrCrCoZ(Z=B, Al, Ga, In) compounds and follow the Slater-Pauling rule, which can be attributed to the great spin-splitting. The calculated formation energies are negative for all the ZrCrCoZ(Z=B, Al, Ga, In) compounds, which indicates that those compounds are in the thermodynamic stability and the possibility of synthesis in experiment.

49 CFR 176.84 - Other requirements for stowage and segregation for cargo vessels and passenger vessels.

Code of Federal Regulations, 2014 CFR

2014-10-01

...” flammable liquids. 29 Stow “away from” ammonium compounds. 30 Stow “away from” animal or vegetable oils. 31... vegetable oils. 55 Stow “separated from” ammonia. 56 Stow “separated from” ammonium compounds. 57 Stow... hexahydrate solution, uranium metal hexahydrate solution, uranium metal pyrophoric and thorium metal...

49 CFR 176.84 - Other requirements for stowage and segregation for cargo vessels and passenger vessels.

Code of Federal Regulations, 2013 CFR

2013-10-01

...” flammable liquids. 29 Stow “away from” ammonium compounds. 30 Stow “away from” animal or vegetable oils. 31... vegetable oils. 55 Stow “separated from” ammonia. 56 Stow “separated from” ammonium compounds. 57 Stow... hexahydrate solution, uranium metal hexahydrate solution, uranium metal pyrophoric and thorium metal...

Nonaqueous method for dissolving lanthanide and actinide metals

DOEpatents

Crisler, L.R.

1975-11-11

Lanthanide and actinide beta-diketonate complex molecular compounds are produced by reacting a beta-diketone compound with a lanthanide or actinide element in the elemental metallic state in a mixture of carbon tetrachloride and methanol.

Selective Sorbents For Purification Of Hydrocarbons

DOEpatents

Yang, Ralph T.; Yang, Frances H.; Takahashi, Akira; Hernandez-Maldonado, Arturo J.

2006-04-18

A method for removing thiophene and thiophene compounds from liquid fuel includes contacting the liquid fuel with an adsorbent which preferentially adsorbs the thiophene and thiophene compounds. The adsorption takes place at a selected temperature and pressure, thereby producing a non-adsorbed component and a thiophene/thiophene compound-rich adsorbed component. The adsorbent includes either a metal or a metal ion that is adapted to form p-complexation bonds with the thiophene and/or thiophene compounds, and the preferential adsorption occurs by p-complexation. A further method includes selective removal of aromatic compounds from a mixture of aromatic and aliphatic compounds.

Selective sorbents for purification of hydrocarbons

DOEpatents

Yang, Ralph T.; Hernandez-Maldonado, Arturo J.; Yang, Frances H.; Takahashi, Akira

2006-08-22

A method for removing thiophene and thiophene compounds from liquid fuel includes contacting the liquid fuel with an adsorbent which preferentially adsorbs the thiophene and thiophene compounds. The adsorption takes place at a selected temperature and pressure, thereby producing a non-adsorbed component and a thiophene/thiophene compound-rich adsorbed component. The adsorbent includes either a metal or a metal cation that is adapted to form .pi.-complexation bonds with the thiophene and/or thiophene compounds, and the preferential adsorption occurs by .pi.-complexation. A further method includes selective removal of aromatic compounds from a mixture of aromatic and aliphatic compounds.

Selective sorbents for purification of hydrocarbons

DOEpatents

Yang, Ralph T.; Yang, Frances H.; Takahashi, Akira; Hernandez-Maldonado, Arturo J.

2006-05-30

A method for removing thiophene and thiophene compounds from liquid fuel includes contacting the liquid fuel with an adsorbent which preferentially adsorbs the thiophene and thiophene compounds. The adsorption takes place at a selected temperature and pressure, thereby producing a non-adsorbed component and a thiophene/thiophene compound-rich adsorbed component. The adsorbent includes either a metal or a metal cation that is adapted to form .pi.-complexation bonds with the thiophene and/or thiophene compounds, and the preferential adsorption occurs by .pi.-complexation. A further method includes selective removal of aromatic compounds from a mixture of aromatic and aliphatic compounds.

Selective sorbents for purification of hydrocartons

DOEpatents

Yang, Ralph T.; Yang, Frances H.; Takahashi, Akira; Hermandez-Maldonado, Arturo J.

2006-12-12

A method for removing thiophene and thiophene compounds from liquid fuel includes contacting the liquid fuel with an adsorbent which preferentially adsorbs the thiophene and thiophene compounds. The adsorption takes place at a selected temperature and pressure, thereby producing a non-adsorbed component and a thiophene/thiophene compound-rich adsorbed component. The adsorbent includes either a metal or a metal ion that is adapted to form .pi.-complexation bonds with the thiophene and/or thiophene compounds, and the preferential adsorption occurs by .pi.-complexation. A further method includes selective removal of aromatic compounds from a mixture of aromatic and aliphatic compounds.

Progress and Perspective of Electrocatalytic CO2 Reduction for Renewable Carbonaceous Fuels and Chemicals.

PubMed

Zhang, Wenjun; Hu, Yi; Ma, Lianbo; Zhu, Guoyin; Wang, Yanrong; Xue, Xiaolan; Chen, Renpeng; Yang, Songyuan; Jin, Zhong

2018-01-01

The worldwide unrestrained emission of carbon dioxide (CO 2 ) has caused serious environmental pollution and climate change issues. For the sustainable development of human civilization, it is very desirable to convert CO 2 to renewable fuels through clean and economical chemical processes. Recently, electrocatalytic CO 2 conversion is regarded as a prospective pathway for the recycling of carbon resource and the generation of sustainable fuels. In this review, recent research advances in electrocatalytic CO 2 reduction are summarized from both experimental and theoretical aspects. The referred electrocatalysts are divided into different classes, including metal-organic complexes, metals, metal alloys, inorganic metal compounds and carbon-based metal-free nanomaterials. Moreover, the selective formation processes of different reductive products, such as formic acid/formate (HCOOH/HCOO - ), monoxide carbon (CO), formaldehyde (HCHO), methane (CH 4 ), ethylene (C 2 H 4 ), methanol (CH 3 OH), ethanol (CH 3 CH 2 OH), etc. are introduced in detail, respectively. Owing to the limited energy efficiency, unmanageable selectivity, low stability, and indeterminate mechanisms of electrocatalytic CO 2 reduction, there are still many tough challenges need to be addressed. In view of this, the current research trends to overcome these obstacles in CO 2 electroreduction field are summarized. We expect that this review will provide new insights into the further technique development and practical applications of CO 2 electroreduction.

Metallo-organic decomposition films

NASA Technical Reports Server (NTRS)

Gallagher, B. D.

1985-01-01

A summary of metallo-organic deposition (MOD) films for solar cells was presented. The MOD materials are metal ions compounded with organic radicals. The technology is evolving quickly for solar cell metallization. Silver compounds, especially silver neodecanoate, were developed which can be applied by thick-film screening, ink-jet printing, spin-on, spray, or dip methods. Some of the advantages of MOD are: high uniform metal content, lower firing temperatures, decomposition without leaving a carbon deposit or toxic materials, and a film that is stable under ambient conditions. Molecular design criteria were explained along with compounds formulated to date, and the accompanying reactions for these compounds. Phase stability and the other experimental and analytic results of MOD films were presented.

Trace desulfurization. [DOE patent application

DOEpatents

Chen, H.L.; Stevens, C.G.

A method for reducing a trace concentration of sulfur-containing compounds in a gas stream from about one part in 10/sup 4/ to about one part in 10/sup 7/. The method includes the steps of irradiating the gas stream with an energy source which has a central emission frequency chosen to substantially match a wavelength of energy absorption of the sulfur-containing compounds and of subsequently contacting the gas stream with a reactive surface which includes a reactant selected from elemental metals and metal oxides so that metallic sulfur-containing compounds are formed. The reduction in concentration allows the gas stream to be processed in certain reactions having catalysts which would otherwise be poisoned by the sulfur-containing compounds.

Preparation of transparent conductors ferroelectric memory materials and ferrites

DOEpatents

Bhattacharya, Raghu Nath; Ginley, David S.

1998-01-01

A process for the preparation by electrodeposition of metal oxide film and powder compounds for ferroelectric memory materials and ferrites wherein the metal oxide includes a plurality of metals. The process comprises providing an electrodeposition bath, providing soluble salts of the metals to this bath, electrically energizing the bath to thereby cause formation of a recoverable film of metal on the electrode, recovering the resultant film as a film or a powder, and recovering powder formed on the floor of the bath. The films and powders so produced are subsequently annealed to thereby produce metal oxide for use in electronic applications. The process can be employed to produce metal-doped metal oxide film and powder compounds for transparent conductors. The process for preparation of these metal-doped metal oxides follows that described above.

Theory versus experiment for a family of single-layer compounds with a similar atomic arrangement: (Tl,X )/Si(111 )√{3 }×√{3 }(X =Pb,Sn,Bi,Sb,Te,Se)

NASA Astrophysics Data System (ADS)

Matetskiy, A. V.; Kibirev, I. A.; Mihalyuk, A. N.; Eremeev, S. V.; Gruznev, D. V.; Bondarenko, L. V.; Tupchaya, A. Y.; Zotov, A. V.; Saranin, A. A.

2017-08-01

Two-dimensional compounds made of one monolayer of Tl and one-third monolayer of Pb, Bi, Te, or Se (but not of Sn or Sb) on Si(111) have been found to have a similar atomic arrangement which can be visualized as a √{3 }×√{3 } -periodic honeycomb network of chained Tl trimers with atoms of the second adsorbate occupying the centers of the honeycomb units. Structural and electronic properties of the compounds have been examined in detail theoretically using density functional theory (DFT) calculations and experimentally using low-energy electron diffraction (LEED), scanning tunneling microscopy (STM), and angle-resolved photoelectron spectroscopy (ARPES) observations. It has been found that though structural parameters of the compounds are very similar for all species, the only common feature of their band structure is a considerable spin-splitting of the surface-state bands, while other basic electronic properties vary greatly with a change of species. The Tl-Pb compound is strongly metallic with two metallic surface-state bands; the Tl-Bi compound is also metallic but with a single metallic band; the Tl-Te and Tl-Se compounds appear to be insulators.

Synthesis of metal complexes involving Schiff base ligand with methylenedioxy moiety: spectral, thermal, XRD and antimicrobial studies.

PubMed

Sundararajan, M L; Jeyakumar, T; Anandakumaran, J; Karpanai Selvan, B

2014-10-15

Metal complexes of Zn(II), Cd(II), Ni(II), Cu(II), Fe(III), Co(II), Mn(II) Hg(II), and Ag(I) have been synthesized from Schiff base ligand, prepared by the condensation of 3,4-(methylenedioxy)aniline and 5-bromo salicylaldehyde. All the compounds have been characterized by using elemental analysis, molar conductance, FT-IR, UV-Vis, (1)H NMR, (13)C NMR, mass spectra, powder XRD and thermal analysis (TG/DTA) technique. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). The FT-IR, (1)H NMR, (13)C NMR and UV-Vis spectral data suggest that the ligand coordinate to the metal atom by imino nitrogen and phenolic oxygen as bidentate manner. Mass spectral data further support the molecular mass of the compounds and their structure. Powder XRD indicates the crystalline state and morphology of the ligand and its metal complexes. The thermal behaviors of the complexes prove the presence of lattice as well as coordinated water molecules in the complexes. Melting point supports the thermal stability of all the compounds. The in vitro antimicrobial effects of the synthesized compounds were tested against five bacterial and three fungal species by well diffusion method. Antioxidant activities have also been performed for all the compounds. Metal complexes show more biological activity than the Schiff base. Copyright © 2014 Elsevier B.V. All rights reserved.

Green synthesis of nano sized transition metal complexes containing heterocyclic Schiff base: Structural and morphology characterization and bioactivity study

NASA Astrophysics Data System (ADS)

Jawoor, Shailaja S.; Patil, Sangamesh A.; Kumbar, Mahantesh; Ramawadgi, Prashant B.

2018-07-01

In the current involvement of our research work in coordination chemistry, novel transition metal complexes were synthesized from regular reflux method and hydrothermal method using Schiff base prepared via condensation of ethyl 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate with 8-carbaldehyde-7-hydroxy-4-methylcoumarin. All the synthesized compounds were interpreted using different analytical, physicochemical and spectral methods such as magnetic moment measurement, FT-IR, 1H and 13C NMR, GCMS/ESI-MS, UV/Vis spectroscopy and TGA. The size and morphology of the nano metal complexes were determined using atomic force microscope (AFM), field emission scanning electron spectroscopy (FE-SEM) and X-ray powder diffraction (PXRD). The non-electrolytic nature of the metal complexes was confirmed by molar conductance studies. The obtained FT-IR data supports the binding of metal ion to Schiff base. Elemental analysis study suggests [ML2(H2O)2] stoichiometry, here M = Co(II), Ni(II) and Cu(II), L = deprotonated ligand. Electronic spectral results reveal six-coordinated geometry for the synthesized metal complexes. All the tested compounds show good DNA cleavage (Calf Thymus DNA) and in vitro anticancer activity (PA-I cell line), the activity results for the tested compounds are prominent and compound 9 exhibited a little enhanced activity than the other tested compounds.

Peroxotitanates for Biodelivery of Metals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hobbs, David; Elvington, M.

2009-02-11

Metal-based drugs are largely undeveloped in pharmacology. One limiting factor is the systemic toxicity of metal-based compounds. A solid-phase, sequestratable delivery agent for local delivery of metals could reduce systemic toxicity, facilitating new drug development in this nascent area. Amorphous peroxotitanates (APT) are ion exchange materials with high affinity for several heavy metal ions, and have been proposed to deliver or sequester metal ions in biological contexts. In the current study, we tested a hypothesis that APT are able to deliver metals or metal compounds to cells. We exposed fibroblasts (L929) or monocytes (THP1) to metal-APT materials for 72 hmore » in vitro, then measured cellular mitochondrial activity (SDH-MTT method) to assess the biological impact of the metal-APT materials vs. metals or APT alone. APT alone did not significantly affect cellular mitochondrial activity, but all metal-APT materials suppressed the mitochondrial activity of fibroblasts (by 30-65% of controls). The concentration of metal-APT materials required to suppress cellular mitochondrial activity was below that required for metals alone, suggesting that simple extracellular release of the metals from the metal-APT materials was not the primary mechanism of mitochondrial suppression. In contrast to fibroblasts, no metal-APT material had a measurable effect on THP1 monocyte mitochondrial activity, despite potent suppression by metals alone. This latter result suggested that 'biodelivery' by metal-APT materials may be cell type-specific. Therefore, it appears that APT are plausible solid phase delivery agents of metals or metal compounds to some types of cells for potential therapeutic effect.« less

Surface Modification and Nanojunction Fabrication with Molecular Metal Wires

DTIC Science & Technology

2014-02-17

Title: Transition Metal Complexes of a Super Rigid Anthyridine Ligand: Structural, Magnetic and DFT Studies. Transition metal complexes of iron ( II ...Compounds with Masked Diazonium Capping Groups (J. Organomet. Chem. 2013, 745, 93). (3) New Diruthenium( II ,III) Compounds Bearing Terminal Olefin Groups...2012, 36, 2340). (2) Synthesis , Structure, Magnetism, and Single Molecular Conductance of Linear Trinickel String Complexes with Sulfur-Containing

Dipole moments and solvatochromism of metal complexes: principle photophysical and theoretical approach.

PubMed

Loukova, Galina V; Milov, Alexey A; Vasiliev, Vladimir P; Minkin, Vladimir I

2016-07-21

For metal-based compounds, the ground- and excited-state dipole moments and the difference thereof are, for the first time, obtained both experimentally and theoretically using solvatochromic equations and DFT/B3LYP/QZVP calculations. The approach is suggested to be promising and easily accessible, and can be universal to elucidate the electronic properties of metal-based compounds.

Durable hydrophobic coating composition for metallic surfaces and method for the preparation of the composition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Jiong

A durable hydrophobic coating composition containing fluorinated silanes for metallic surfaces, such as stainless steel surfaces. The composition includes at least one fluorine-containing silane compound, at least one phosphorus-containing silane compound, and at least one hydrolysable compound. This coating is suitable for condenser tubes, among other applications, to promote dropwise condensation.

Inorganic nanotubes and fullerene-like nanoparticles at the crossroad between materials science and nanotechnology

NASA Astrophysics Data System (ADS)

Tenne, Reshef

2014-03-01

This presentation is aimed at underlying the principles, synthesis, characterization and applications of inorganic nanotubes (INT) and fullerne-like (IF) nanoparticles (NP) from 2-D layered compounds. While the high temperature synthesis and study of IF materials and INT from layered metal dichalcogenides, like WS2 and MoS2 remain a major challenge, progress with the synthesis of IF and INT structures from various other compounds has been realized, as well. Intercalation and doping of these nanostructures, which lends itself to interesting electronic properties, has been realized, too. Core-shell nanotubular structures, like PbI2@WS2 and SnS/SnS2 and PbS/NbS2 nanotubes from ``misfit'' compounds have been recently reported. Re doping of the IF and INT endow them with interesting electrical and other physio-chemical properties. Major progress has been achieved in elucidating the structure of INT and IF using advanced microscopy techniques, like aberration corrected TEM and electron tomography. Also recently, scaling up efforts in collaboration with ``NanoMaterials'' resulted in multikilogram production of (almost) pure multiwall WS2 nanotubes phases. Extensive experimental and theoretical analysis of the mechanical properties of individual INT and more recently IF NP was performed casting light on their behavior in the macroscopic world. IF-MS2 (M =W,Mo, etc) were shown to be superior solid lubricants in variety of forms, including an additive to various lubricating fluids/greases and for various self-lubricating coating. Full commercialization of products based on this technology is taking place now.

Investigation of metal–dithiolate fold angle effects: Implications for molybdenum and tungsten enzymes

PubMed Central

Joshi, Hemant K.; Cooney, J. Jon A.; Inscore, Frank E.; Gruhn, Nadine E.; Lichtenberger, Dennis L.; Enemark, John H.

2003-01-01

Gas-phase photoelectron spectroscopy and density functional theory have been used to investigate the interactions between the sulfur π-orbitals of arene dithiolates and high-valent transition metals as minimum molecular models of the active site features of pyranopterin Mo/W enzymes. The compounds (Tp*)MoO(bdt) (compound 1), Cp2Mo(bdt) (compound 2), and Cp2Ti(bdt) (compound 3) [where Tp* is hydrotris(3,5-dimethyl-1-pyrazolyl)borate, bdt is 1,2-benzenedithiolate, and Cp is η5- cyclopentadienyl] provide access to three different electronic configurations of the metal, formally d1, d2, and d0, respectively. The gas-phase photoelectron spectra show that ionizations from occupied metal and sulfur based valence orbitals are more clearly observed in compounds 2 and 3 than in compound 1. The observed ionization energies and characters compare very well with those calculated by density functional theory. A “dithiolate-folding-effect” involving an interaction of the metal in-plane and sulfur-π orbitals is proposed to be a factor in the electron transfer reactions that regenerate the active sites of molybdenum and tungsten enzymes. PMID:12655066

A review of pitfalls and progress in chelation treatment of metal poisonings.

PubMed

Andersen, Ole; Aaseth, Jan

2016-12-01

Most acute and chronic human metal poisonings are due to oral or inhalation exposure. Almost 80% of published animal experiments on chelation in metal poisoning used single or repeated intraperitoneal, intramuscular or intravenous administration of metal and chelator, impeding extrapolation to clinical settings. Intramuscular administration of dimercaptopropanol (BAL) has until now been used in acute arsenic, lead, and mercury poisonings, but repeated BAL administration increased the brain uptake of As, Pb and Hg in experimental animals. Also, diethyl dithiocarbamate (DDC) has been used as antidote in acute experimental animal parenteral Cd poisoning, and both DDC and tetraethylthiuram disulfide (TTD, disulfiram, Antabuse) have been used in nickel allergic patients. However, even one dose of DDC given immediately after oral Cd or Ni increased their brain uptake considerably. The calcium salt of ethylenediamminetetraacetic acid (CaEDTA) but not dimercaptosuccinic acid (DMSA) increased the brain uptake of Pb. In oral Cd or Hg poisoning, early oral administration of DMSA or dimercaptopropane sulfonate (DMPS) increased survival and reduced intestinal metal uptake. Oral administration of Prussian Blue or resins with fixed chelating groups that are not absorbed offer chelation approaches for decorporation after oral exposure to various metals. Diethylenetriaminepentaacetic acid (DTPA) nebulizers for pulmonary chelation after inhalation exposure need further development. Also, combined chelation with more than one compound may offer extensive advances. Solid knowledge on the chemistry of metal chelates together with relevant animal experiments should guide development of chelation procedures to alleviate and not aggravate the clinical status of poisoned patients. Copyright © 2016 Elsevier GmbH. All rights reserved.

Process for preparing phthalocyanine polymer from imide containing bisphthalonitrile

NASA Technical Reports Server (NTRS)

Achar, Bappalige N. (Inventor); Fohlen, George M. (Inventor); Parker, John A. (Inventor)

1987-01-01

Imide-linked bisphthalonitrile compounds are prepared by combining a dicyano aromatic diamine and an organic dianhydride to produce an amic acid linked bisphthalonitrile compound. The amic acid linked bisphthalonitrile compound is dehydrocyclized to produce the imide-linked bisphthalonitrile compounds. The imide-linked bisphthalonitrile compounds may be polymerized to produce a phythalocyanine polymer by heating the imide-linked bisphthalonitrile compound, either alone or in the presence of a metal powder or a metal salt. These compounds are useful in the coating, laminating and molding arts. The polymers are useful in composite matrix resins where increased fire resistance, toughness and resistance to moisture are required, particularly as secondary structures in aircraft and spacecraft.

PEROXOTITANATE- AND MONOSODIUM METAL-TITANATE COMPOUNDS AS INHIBITORS OF BACTERIAL GROWTH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hobbs, D.

2011-01-19

Sodium titanates are ion-exchange materials that effectively bind a variety of metal ions over a wide pH range. Sodium titanates alone have no known adverse biological effects but metal-exchanged titanates (or metal titanates) can deliver metal ions to mammalian cells to alter cell processes in vitro. In this work, we test a hypothesis that metal-titanate compounds inhibit bacterial growth; demonstration of this principle is one prerequisite to developing metal-based, titanate-delivered antibacterial agents. Focusing initially on oral diseases, we exposed five species of oral bacteria to titanates for 24 h, with or without loading of Au(III), Pd(II), Pt(II), and Pt(IV), andmore » measuring bacterial growth in planktonic assays through increases in optical density. In each experiment, bacterial growth was compared with control cultures of titanates or bacteria alone. We observed no suppression of bacterial growth by the sodium titanates alone, but significant (p < 0.05, two-sided t-tests) suppression was observed with metal-titanate compounds, particularly Au(III)-titanates, but with other metal titanates as well. Growth inhibition ranged from 15 to 100% depending on the metal ion and bacterial species involved. Furthermore, in specific cases, the titanates inhibited bacterial growth 5- to 375-fold versus metal ions alone, suggesting that titanates enhanced metal-bacteria interactions. This work supports further development of metal titanates as a novel class of antibacterials.« less

Composites for removing metals and volatile organic compounds and method thereof

DOEpatents

Coronado, Paul R [Livermore, CA; Coleman, Sabre J [Oakland, CA; Reynolds, John G [San Ramon, CA

2006-12-12

Functionalized hydrophobic aerogel/solid support structure composites have been developed to remove metals and organic compounds from aqueous and vapor media. The targeted metals and organics are removed by passing the aqueous or vapor phase through the composite which can be in molded, granular, or powder form. The composites adsorb the metals and the organics leaving a purified aqueous or vapor stream. The species-specific adsorption occurs through specific functionalization of the aerogels tailored towards specific metals and/or organics. After adsorption, the composites can be disposed of or the targeted metals and/or organics can be reclaimed or removed and the composites recycled.

Methods for the synthesis of deuterated vinyl pyridine monomers

DOEpatents

Hong, Kunlun; Yang, Jun; Bonnesen, Peter V

2014-02-25

Methods for synthesizing deuterated vinylpyridine compounds of the Formula (1), wherein the method includes: (i) deuterating an acyl pyridine of the Formula (2) in the presence of a metal catalyst and D.sub.2O, wherein the metal catalyst is active for hydrogen exchange in water, to produce a deuterated acyl compound of Formula (3); (ii) reducing the compound of Formula (3) with a deuterated reducing agent to convert the acyl group to an alcohol group, and (iii) dehydrating the compound produced in step (ii) with a dehydrating agent to afford the vinylpyridine compound of Formula (1). The resulting deuterated vinylpyridine compounds are also described.

Methods for the synthesis of deuterated vinyl pyridine monomers

DOEpatents

Hong, Kunlun; Yang, Jun; Bonnesen, Peter V

2015-01-13

Methods for synthesizing deuterated vinylpyridine compounds of the Formula (1), wherein the method includes: (i) deuterating an acyl pyridine of the Formula (2) in the presence of a metal catalyst and D.sub.2O, wherein the metal catalyst is active for hydrogen exchange in water, to produce a deuterated acyl compound of Formula (3); (ii) reducing the compound of Formula (3) with a deuterated reducing agent to convert the acyl group to an alcohol group, and (iii) dehydrating the compound produced in step (ii) with a dehydrating agent to afford the vinylpyridine compound of Formula (1). The resulting deuterated vinylpyridine compounds are also described.

Synthesis and Processing of Ultra-High Temperature Metal Carbide and Metal Diboride Nanocomposite Materials

DTIC Science & Technology

2008-04-15

cellulose acetate polymers, and diols. Common sol- uble metal/metal oxide-bearing materials are metal alkoxides, metal diketonates, and metal ... carboxylates . Metal-organic compounds are usually subjected to hydrolysis and condensa- tion reactions to produce polymeric or colloidal metal-oxide

Precision Sheet Metal. Progress Record and Theory Outline.

ERIC Educational Resources Information Center

Connecticut State Dept. of Education, Hartford. Div. of Vocational-Technical Schools.

This combination progress record and course outline is designed for use by individuals teaching a course in precision sheet metal. Included among the topics addressed in the course are the following: employment opportunities in metalworking, measurement and layout, orthographic projection, precision sheet metal drafting, simple layout, hand tools,…

Transition metal-catalyzed process for addition of amines to carbon-carbon double bonds

DOEpatents

Hartwig, John F.; Kawatsura, Motoi; Loeber, Oliver

2002-01-01

The present invention is directed to a process for addition of amines to carbon-carbon double bonds in a substrate, comprising: reacting an amine with a compound containing at least one carbon-carbon double bond in the presence a transition metal catalyst under reaction conditions effective to form a product having a covalent bond between the amine and a carbon atom of the former carbon-carbon double bond. The transition metal catalyst comprises a Group 8 metal and a ligand containing one or more 2-electron donor atoms. The present invention is also directed to enantioselective reactions of amine compounds with compounds containing carbon-carbon double bonds, and a calorimetric assay to evaluate potential catalysts in these reactions.

N-Acetylcysteine interacts with copper to generate hydrogen peroxide and selectively induce cancer cell death

PubMed Central

Zheng, Jie; Lou, Jessica R.; Zhang, Xiao-Xi; Benbrook, Doris M.; Hanigan, Marie H.; Lind, Stuart E.; Ding, Wei-Qun

2013-01-01

A variety of metal-binding compounds have been found to exert anti-cancer activity. We postulated that N-acetylcysteine (NAC), which is a membrane-permeable metal-binding compound, might have anti-cancer activity in the presence of metals. We found that NAC/Cu(II) significantly alters growth and induces apoptosis in human cancer lines, yet NAC/Zn(II) and NAC/Fe(III) do not. We further confirmed that this cytotoxicity of NAC/Cu(II) is attributed to reactive oxygen species (ROS). These findings indicate that the combination of Cu(II) and thiols generates cytotoxic ROS that induce apoptosis in cancer cells. They also indicate a fourth class of anti-neoplastic metal-binding compounds, the “ROS generator”. PMID:20667650

Process for production of a metal hydride

DOEpatents

Allen, Nathan Tait; Butterick, III, Robert; Chin, Arthur Achhing; Millar, Dean Michael; Molzahn, David Craig

2014-08-12

A process for production of a metal hydride compound MH.sub.x, wherein x is one or two and M is an alkali metal, Be or Mg. The process comprises combining a compound of formula (R.sup.1O).sub.xM with aluminum, hydrogen and at least one metal selected from among titanium, zirconium, hafnium, niobium, vanadium, tantalum and iron to produce a compound of formula MH.sub.x. R.sup.1 is phenyl or phenyl substituted by at least one alkyl or alkoxy group. A mole ratio of aluminum to (R.sup.1O).sub.xM is from 0.1:1 to 1:1. The catalyst is present at a level of at least 200 ppm based on weight of aluminum.

Partial oxidation process for producing a stream of hot purified gas

DOEpatents

Leininger, Thomas F.; Robin, Allen M.; Wolfenbarger, James K.; Suggitt, Robert M.

1995-01-01

A partial oxidation process for the production of a stream of hot clean gas substantially free from particulate matter, ammonia, alkali metal compounds, halides and sulfur-containing gas for use as synthesis gas, reducing gas, or fuel gas. A hydrocarbonaceous fuel comprising a solid carbonaceous fuel with or without liquid hydrocarbonaceous fuel or gaseous hydrocarbon fuel, wherein said hydrocarbonaceous fuel contains halides, alkali metal compounds, sulfur, nitrogen and inorganic ash containing components, is reacted in a gasifier by partial oxidation to produce a hot raw gas stream comprising H.sub.2, CO, CO.sub.2, H.sub.2 O, CH.sub.4, NH.sub.3, HCl, HF, H.sub.2 S, COS, N.sub.2, Ar, particulate matter, vapor phase alkali metal compounds, and molten slag. The hot raw gas stream from the gasifier is split into two streams which are separately deslagged, cleaned and recombined. Ammonia in the gas mixture is catalytically disproportionated into N.sub.2 and H.sub.2. The ammonia-free gas stream is then cooled and halides in the gas stream are reacted with a supplementary alkali metal compound to remove HCl and HF. Alkali metal halides, vaporized alkali metal compounds and residual fine particulate matter are removed from the gas stream by further cooling and filtering. The sulfur-containing gases in the process gas stream are then reacted at high temperature with a regenerable sulfur-reactive mixed metal oxide sulfur sorbent material to produce a sulfided sorbent material which is then separated from the hot clean purified gas stream having a temperature of at least 1000.degree. F.

Partial oxidation process for producing a stream of hot purified gas

DOEpatents

Leininger, T.F.; Robin, A.M.; Wolfenbarger, J.K.; Suggitt, R.M.

1995-03-28

A partial oxidation process is described for the production of a stream of hot clean gas substantially free from particulate matter, ammonia, alkali metal compounds, halides and sulfur-containing gas for use as synthesis gas, reducing gas, or fuel gas. A hydrocarbonaceous fuel comprising a solid carbonaceous fuel with or without liquid hydrocarbonaceous fuel or gaseous hydrocarbon fuel, wherein said hydrocarbonaceous fuel contains halides, alkali metal compounds, sulfur, nitrogen and inorganic ash containing components, is reacted in a gasifier by partial oxidation to produce a hot raw gas stream comprising H{sub 2}, CO, CO{sub 2}, H{sub 2}O, CH{sub 4}, NH{sub 3}, HCl, HF, H{sub 2}S, COS, N{sub 2}, Ar, particulate matter, vapor phase alkali metal compounds, and molten slag. The hot raw gas stream from the gasifier is split into two streams which are separately deslagged, cleaned and recombined. Ammonia in the gas mixture is catalytically disproportionated into N{sub 2} and H{sub 2}. The ammonia-free gas stream is then cooled and halides in the gas stream are reacted with a supplementary alkali metal compound to remove HCl and HF. Alkali metal halides, vaporized alkali metal compounds and residual fine particulate matter are removed from the gas stream by further cooling and filtering. The sulfur-containing gases in the process gas stream are then reacted at high temperature with a regenerable sulfur-reactive mixed metal oxide sulfur sorbent material to produce a sulfided sorbent material which is then separated from the hot clean purified gas stream having a temperature of at least 1000 F. 1 figure.

Use of ionic liquids as coordination ligands for organometallic catalysts

DOEpatents

Li, Zaiwei [Moreno Valley, CA; Tang, Yongchun [Walnut, CA; Cheng,; Jihong, [Arcadia, CA

2009-11-10

Aspects of the present invention relate to compositions and methods for the use of ionic liquids with dissolved metal compounds as catalysts for a variety of chemical reactions. Ionic liquids are salts that generally are liquids at room temperature, and are capable of dissolving a many types of compounds that are relatively insoluble in aqueous or organic solvent systems. Specifically, ionic liquids may dissolve metal compounds to produce homogeneous and heterogeneous organometallic catalysts. One industrially-important chemical reaction that may be catalyzed by metal-containing ionic liquid catalysts is the conversion of methane to methanol.

Preparation of transparent conductors ferroelectric memory materials and ferrites

DOEpatents

Bhattacharya, R.N.; Ginley, D.S.

1998-07-28

A process is described for the preparation by electrodeposition of metal oxide film and powder compounds for ferroelectric memory materials and ferrites wherein the metal oxide includes a plurality of metals. The process comprises providing an electrodeposition bath, providing soluble salts of the metals to this bath, electrically energizing the bath to thereby cause formation of a recoverable film of metal on the electrode, recovering the resultant film as a film or a powder, and recovering powder formed on the floor of the bath. The films and powders so produced are subsequently annealed to thereby produce metal oxide for use in electronic applications. The process can be employed to produce metal-doped metal oxide film and powder compounds for transparent conductors. The process for preparation of these metal-doped metal oxides follows that described above.

Observation of Vacancies, Faults, and Superstructures in Ln5Mo2O12 (Ln = La, Y, and Lu) Compounds with Direct Mo-Mo Bonding.

PubMed

Colabello, Diane M; Sobalvarro, Elizabeth M; Sheckelton, John P; Neuefeind, Joerg C; McQueen, Tyrel M; Khalifah, Peter G

2017-11-06

Among oxide compounds with direct metal-metal bonding, the Y 5 Mo 2 O 12 (A 5 B 2 O 12 ) structural family of compounds has a particularly intriguing low-dimensional structure due to the presence of bioctahedral B 2 O 10 dimers arranged in one-dimensional edge-sharing chains along the direction of the metal-metal bonds. Furthermore, these compounds can have a local magnetic moment due to the noninteger oxidation state (+4.5) of the transition metal, in contrast to the conspicuous lack of a local moment that is commonly observed when oxide compounds with direct metal-metal bonding have integer oxidation states resulting from the lifting of orbital degeneracy typically induced by the metal-metal bonding. Although a monoclinic C2/m structure has been previously proposed for Ln 5 Mo 2 O 12 (Ln = La-Lu and Y) members of this family based on prior single crystal diffraction data, it is found that this structural model misses many important structural features. On the basis of synchrotron powder diffraction data, it is shown that the C2/m monoclinic unit cell represents a superstructure relative to a previously unrecognized orthorhombic Immm subcell and that the superstructure derives from the ordering of interchangeable Mo 2 O 10 and LaO 6 building blocks. The superstructure for this reason is typically highly faulted, as evidenced by the increased breadth of superstructure diffraction peaks associated with a coherence length of 1-2 nm in the c* direction. Finally, it is shown that oxygen vacancies can occur when Ln = La, producing an oxygen deficient stoichiometry of La 5 Mo 2 O 11.55 and an approximately 10-fold reduction in the number of unpaired electrons due to the reduction of the average Mo valence from +4.5 to +4.05, a result confirmed by magnetic susceptibility measurements. This represents the first observation of oxygen vacancies in this family of compounds and provides an important means of continuously tuning the magnetic interactions within the one-dimensional octahedral chains of this system.

The effect of boron concentration on the structure and elastic properties of Ru-Ir alloys: first-principles calculations

NASA Astrophysics Data System (ADS)

Li, Xiaolong; Zhou, Zhaobo; Hu, Riming; Zhou, Xiaolong; Yu, Jie; Liu, Manmen

2018-04-01

The Phase stability, electronic structure, elastic properties and hardness of Ru-Ir alloys with different B concentration were investigated by first principles calculations. The calculated formation enthaplies and cohesive energies show that these compounds are all thermodynamically stable. Information on electronic structure indicates that they possess metallic characteristic and Ru-Ir-B alloys were composed of the Ru-B and Ir-B covalent bond. The elastic properties were calculated, which included bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio and hardness. The calculated results reveal that the plastic of Ru-Ir-B alloys increase with the increase of the content of B atoms, but the hardness of Ru-Ir-B alloys have no substantial progress with the increase of the content of B atoms. However, it is interesting that the hardness of the Ru-Ir-B compound was improved obviously as the B content was higher than 18 atoms because of a phase structure transition.

gem-Difluoroolefination of Diazo Compounds with TMSCF3 or TMSCF2Br: Transition-Metal-Free Cross-Coupling of Two Carbene Precursors.

PubMed

Hu, Mingyou; Ni, Chuanfa; Li, Lingchun; Han, Yongxin; Hu, Jinbo

2015-11-18

A new olefination protocol for transition-metal-free cross-coupling of two carbene fragments arising from two different sources, namely, a nonfluorinated carbene fragment resulting from a diazo compound and a difluorocarbene fragment derived from Ruppert-Prakash reagent (TMSCF3) or TMSCF2Br, has been developed. This gem-difluoroolefination proceeds through the direct nucleophilic addition of diazo compounds to difluorocarbene followed by elimination of N2. Compared to previously reported Cu-catalyzed gem-difluoroolefination of diazo compounds with TMSCF3, which possesses a narrow substrate scope due to a demanding requirement on the reactivity of diazo compounds and in-situ-generated CuCF3, this transition-metal-free protocol affords a general and efficient approach to various disubstituted 1,1-difluoroalkenes, including difluoroacrylates, diaryldifluoroolefins, as well as arylalkyldifluoroolefins. In view of the ready availability of diazo compounds and difluorocarbene reagents and versatile transformations of 1,1-difluoroalkenes, this new gem-difluoroolefination method is expected to find wide applications in organic synthesis.

Formation of fouling deposits on a carbon steel surface from Colombian heavy crude oil under preheating conditions

NASA Astrophysics Data System (ADS)

Muñoz Pinto, D. A.; Cuervo Camargo, S. M.; Orozco Parra, M.; Laverde, D.; García Vergara, S.; Blanco Pinzon, C.

2016-02-01

Fouling in heat exchangers is produced by the deposition of undesired materials on metal surfaces. As fouling progresses, pressure drop and heat transfer resistance is observed and therefore the overall thermal efficiency of the equipment diminishes. Fouling is mainly caused by the deposition of suspended particles, such as those from chemical reactions, crystallization of certain salts, and some corrosion processes. In order to understand the formation of fouling deposits from Colombian heavy oil (API≈12.3) on carbon steel SA 516 Gr 70, a batch stirred tank reactor was used. The reactor was operated at a constant pressure of 340psi while varying the temperature and reaction times. To evaluate the formation of deposits on the metal surfaces, the steel samples were characterized by gravimetric analysis and Scanning Electron Microscopy (SEM). On the exposed surfaces, the results revealed an increase in the total mass derived from the deposition of salt compounds, iron oxides and alkaline metals. In general, fouling was modulated by both the temperature and the reaction time, but under the experimental conditions, the temperature seems to be the predominant variable that controls and accelerates fouling.

Stable surface passivation process for compound semiconductors

DOEpatents

Ashby, Carol I. H.

2001-01-01

A passivation process for a previously sulfided, selenided or tellurated III-V compound semiconductor surface. The concentration of undesired mid-gap surface states on a compound semiconductor surface is reduced by the formation of a near-monolayer of metal-(sulfur and/or selenium and/or tellurium)-semiconductor that is effective for long term passivation of the underlying semiconductor surface. Starting with the III-V compound semiconductor surface, any oxidation present thereon is substantially removed and the surface is then treated with sulfur, selenium or tellurium to form a near-monolayer of chalcogen-semiconductor of the surface in an oxygen-free atmosphere. This chalcogenated surface is then contacted with a solution of a metal that will form a low solubility chalcogenide to form a near-monolayer of metal-chalcogen-semiconductor. The resulting passivating layer provides long term protection for the underlying surface at or above the level achieved by a freshly chalcogenated compound semiconductor surface in an oxygen free atmosphere.

White rot fungi and advanced combined biotechnology with nanomaterials: promising tools for endocrine-disrupting compounds biotransformation.

PubMed

Huang, Danlian; Guo, Xueying; Peng, Zhiwei; Zeng, Guangming; Xu, Piao; Gong, Xiaomin; Deng, Rui; Xue, Wenjing; Wang, Rongzhong; Yi, Huan; Liu, Caihong

2018-08-01

Endocrine-disrupting compounds (EDCs) can interfere with endocrine systems and bio-accumulate through the food chain and even decrease biodiversity in contaminated areas. This review discusses a critical overview of recent research progress in the biotransformation of EDCs (including polychlorinated biphenyl and nonylphenol, and suspected EDCs such as heavy metals and sulfonamide antibiotics) by white rot fungi (WRF) based on techniques with an emphasis on summarizing and analyzing fungal molecular, metabolic and genetic mechanisms. Not only intracellular metabolism which seems to perform essential roles in the ability of WRF to transform EDCs, but also advanced applications are deeply discussed. This review mainly reveals the removal pathway of heavy metal and antibiotic pollutants because the single pollution almost did not exist in a real environment while the combined pollution has become more serious and close to people's life. The trends in WRF technology and its related advanced applications which use the combined technology, including biocatalysis of WRF and adsorption of nanomaterials, to degrade EDCs have also been introduced. Furthermore, challenges and future research needs EDCs biotransformation by WRF are also discussed. This research, referring to metabolic mechanisms and the combined technology of WRF with nanomaterials, undoubtedly contributes to the applications of biotechnology. This review will be of great benefit to an understanding of the trends in biotechnology for the removal of EDCs.

A new metalation complex for organic synthesis and polymerization reactions

NASA Technical Reports Server (NTRS)

Hirshfield, S. M.

1971-01-01

Organometallic complex of N,N,N',N' tetramethyl ethylene diamine /TMEDA/ and lithium acts as metalation intermediate for controlled systhesis of aromatic organic compounds and polymer formation. Complex of TMEDA and lithium aids in preparation of various organic lithium compounds.

[Differential study of the bonding characterization of dental porcelain to Ni-Cr alloys].

PubMed

Wei, Fang; Zhan, De-song; Wang, Yan-yan

2008-10-01

To study the bonding capability when Ni-Cr porcelain alloy was added with Ti, compound rare earth metals and removed the element of Be. Ni-Cr-Ti porcelain alloys manufactured by Institute of Metal Research of Chinese Academy of Sciences were tested. The test alloys were divided into three groups according to whether containing Be and compound rare earth metals or not. And HI BOND Ni-Cr base-metal alloy was chosen as control. The metal-ceramic specimens were prepared for shear test, scanning electron microscope (SEM) and energy spectrum analysis. The shear bond strength of the four groups were analyzed. No significant difference were observed among them (P > 0.05). No crackle was found and they were contacted tightly between the porcelain and metal. The composition and contents of the four groups' interfaces were closed. The shear bond strength of the self-made Ni-Cr-Ti porcelain alloys all can satisfy the clinical requirements. Experimental groups containing Ti, compound rare earth metals and removing the element of Be can be used as better recommendation for clinical practice.

The intra-annular acylamide chelate-coordinated compound: The keto-tautomer of metal (II) milrinone complex

NASA Astrophysics Data System (ADS)

Gong, Yun; Liu, Jinzhi; Tang, Wang; Hu, Changwen

2008-03-01

In the presence of N, N'-dimethyllformamide (DMF), two isostructural metal (II)-milrinone complexes formulated as M(C 12H 8N 3O) 2 (M = Co 1 and Ni 2) have been synthesized and characterized by elemental analysis, IR, TG and single crystal X-ray diffraction. The two compounds crystallize in the tetragonal system, chiral space group P4 32 12. They exhibit similar two dimensional (2D) square grid-like framework, in which milrinone acts as a ditopic ligand with its terminal pyridine and intra-annular acylamide groups covalently bridging different metal centers. The intra-annular acylamide ligand shows a chelate-coordinated mode. Compounds 1 and 2 are stable under 200 °C. Compound 3 formulated as (C 12H 9N 3O) 4·H 2O was obtained in the presence of water, the water molecule in the structure leads to the racemization of compound 3 and it crystallizes in the monoclinic system, non-chiral space group P2 1/ c. Milrinone exhibits a keto-form in the three compounds and compounds 1- 3 exhibit different photoluminescence properties.

Water Analysis.

ERIC Educational Resources Information Center

MacCarthy, Patrick; And Others

1989-01-01

Analytical methods are reviewed for: alkali and alkaline earth metals; transition metals; precious metals; group 12, 13, 14, and 15 metals, nonmetals; radionuclides; multiple metals; anions; gases; chromatography; mass spectroscopy; photometry; sampling; volatile compounds; surfactants; detergents; pesticides; herbicides; and fungicides. (MVL)

Metal aminocarboxylate coordination polymers with chain and layered structures.

PubMed

Dan, Meenakshi; Rao, C N R

2005-11-18

The synthesis and structures of metal aminocarboxylates prepared in acidic, neutral, or alkaline media have been explored with the purpose of isolating coordination polymers with linear chain and two-dimensional layered structures. Metal glycinates of the formulae [CoCl2(H2O)2(CO2CH2NH3)] (I), [MnCl2(CO2CH2NH3)2] (II), and [Cd3Cl6(CO2CH2NH3)4] (III) with one-dimensional chain structures have been obtained by the reaction of the metal salts with glycine in an acidic medium under hydro/solvothermal conditions. These chain compounds contain glycine in the zwitterionic form. 4-Aminobutyric acid transforms to a cyclic amide under such reaction conditions, and the amide forms a chain compound of the formula [CdBr2(C4H7NO)2] (IV). Glycine in the zwitterionic form also forms a two-dimensional layered compound of the formula [Mn(H2O)2(CO2CH2NH3)2]Br2 (V). 6-Aminocaproic acid under alkaline conditions forms layered compounds with metals at room temperature, the metal being coordinated both by the amino nitrogen and the carboxyl oxygen atoms. Of the two layered compounds [Cd{CO2(CH2)5NH2}2]2 H2O (VI) and [Cu{CO2(CH2)5NH2}2]2 H2O (VII), the latter has voids in which water molecules reside.

T-screen and yeast assay for the detection of the thyroid-disrupting activities of cadmium, mercury, and zinc.

PubMed

Li, Jian; Liu, Yun; Kong, Dongdong; Ren, Shujuan; Li, Na

2016-05-01

In the present study, a two-hybrid yeast bioassay and a T-screen were used to screen for the thyroid receptor (TR)-disrupting activity of select metallic compounds (CdCl2, ZnCl2, HgCl2, CuSO4, MnSO4, and MgSO4). The results reveal that none of the tested metallic compounds showed TR-agonistic activity, whereas ZnCl2, HgCl2, and CdCl2 demonstrated TR antagonism. For the yeast assay, the dose-response relationship of these metallic compounds was established, and the concentrations producing 20 % of the maximum effect of ZnCl2, HgCl2, and CdCl2 were 9.1 × 10(-5), 3.2 × 10(-6), and 1.2 × 10(-6) mol/L, respectively. The T-screen also supported the finding that ZnCl2, HgCl2, and CdCl2 decreased the cell proliferation at concentrations ranging from 10(-6) to 10(-4) mol/L. Furthermore, the thyroid-disrupting activity of metallic compounds in environmental water samples collected from the Guanting Reservoir, Beijing, China was evaluated. Solid-phase extraction was used to separate the organic extracts, and a modified two-hybrid yeast bioassay revealed that the metallic compounds in the water samples could affect thyroid hormone-induced signaling by decreasing the binding of the thyroid hormone. The addition of ethylenediaminetetraacetic acid (30 mg/L) could eliminate the effects. Thus, the cause(s) of the thyroid toxicity in the water samples appeared to be partly related to the metallic compounds.

Process and composition for drying of gaseous hydrogen halides

DOEpatents

Tom, Glenn M.; Brown, Duncan W.

1989-08-01

A process for drying a gaseous hydrogen halide of the formula HX, wherein X is selected from the group consisting of bromine, chlorine, fluorine, and iodine, to remove water impurity therefrom, comprising: contacting the water impurity-containing gaseous hydrogen halide with a scavenger including a support having associated therewith one or more members of the group consisting of: (a) an active scavenging moiety selected from one or more members of the group consisting of: (i) metal halide compounds dispersed in the support, of the formula MX.sub.y ; and (ii) metal halide pendant functional groups of the formula -MX.sub.y-1 covalently bonded to the support, wherein M is a y-valent metal, and y is an integer whose value is from 1 to 3; (b) corresponding partially or fully alkylated compounds and/or pendant functional groups, of the metal halide compounds and/or pendant functional groups of (a); wherein the alkylated compounds and/or pendant functional groups, when present, are reactive with the gaseous hydrogen halide to form the corresponding halide compounds and/or pendant functional groups of (a); and M being selected such that the heat of formation, .DELTA.H.sub.f of its hydrated halide, MX.sub.y.(H.sub.2 O).sub.n, is governed by the relationship: .DELTA.H.sub.f .gtoreq.n.times.10.1 kilocalories/mole of such hydrated halide compound wherein n is the number of water molecules bound to the metal halide in the metal halide hydrate. Also disclosed is an appertaining scavenger composition and a contacting apparatus wherein the scavenger is deployed in a bed for contacting with the water impurity-containing gaseous hydrogen halide.

Effect of Metals, Metalloids and Metallic Nanoparticles on Microalgae Growth and Industrial Product Biosynthesis: A Review

PubMed Central

Miazek, Krystian; Iwanek, Waldemar; Remacle, Claire; Richel, Aurore; Goffin, Dorothee

2015-01-01

Microalgae are a source of numerous compounds that can be used in many branches of industry. Synthesis of such compounds in microalgal cells can be amplified under stress conditions. Exposure to various metals can be one of methods applied to induce cell stress and synthesis of target products in microalgae cultures. In this review, the potential of producing diverse biocompounds (pigments, lipids, exopolymers, peptides, phytohormones, arsenoorganics, nanoparticles) from microalgae cultures upon exposure to various metals, is evaluated. Additionally, different methods to alter microalgae response towards metals and metal stress are described. Finally, possibilities to sustain high growth rates and productivity of microalgal cultures in the presence of metals are discussed. PMID:26473834

Method for forming hermetic seals

NASA Technical Reports Server (NTRS)

Gallagher, Brian D.

1987-01-01

The firmly adherent film of bondable metal, such as silver, is applied to the surface of glass or other substrate by decomposing a layer of solution of a thermally decomposable metallo-organic deposition (MOD) compound such as silver neodecanoate in xylene. The MOD compound thermally decomposes into metal and gaseous by-products. Sealing is accomplished by depositing a layer of bonding metal, such as solder or a brazing alloy, on the metal film and then forming an assembly with another high melting point metal surface such as a layer of Kovar. When the assembly is heated above the temperature of the solder, the solder flows, wets the adjacent surfaces and forms a hermetic seal between the metal film and metal surface when the assembly cools.

Process for removal of water and silicon mu-oxides from chlorosilanes

DOEpatents

Tom, Glenn M.; McManus, James V.

1992-03-10

A scavenger composition having utility for removal of water and silicon mu-oxide impurities from chlorosilanes, such scavenger composition comprising: (a) a support; and (b) associated with the support, one or more compound(s) selected from the group consisting of compounds of the formula: R.sub.a-x MCl.sub.x wherein: M is a metal selected from the group consisting of the monovalent metals lithium, sodium, and potassium; the divalent metals magnesium, strontium, barium, and calcium; and the trivalent metal aluminum; R is alkyl; a is a number equal to the valency of metal M; and x is a number having a value of from 0 to a, inclusive; and wherein said compound(s) of the formula R.sub.a-x MCl.sub.x have been activated for impurity-removal service by a reaction scheme selected from those of the group consisting of: (i) reaction of such compound(s) with hydrogen chloride to form a first reaction product therefrom, followed by reaction of the first reaction product with a chlorosilane of the formula: SiH.sub.4-y Cl.sub.y, wherein y is a number having a value of from 1 to 3, inclusive; and (ii) reaction of such compound(s) with a chlorosilane of the formula: SiH.sub.4-y Cl.sub.y wherein y is a number having a value of 1 to 3, inclusive. A corresponding method of making the scavenger composition, and of purifying a chlorosilane which contains oxygen and silicon mu-oxide impurities, likewise are disclosed, together with a purifier apparatus, in which a bed of the scavenger composition is disposed. The composition, purification process, and purifier apparatus of the invention have utility in purifying gaseous chlorosilanes which are employed in the semiconductor industry as silicon source reagents for forming epitaxial silicon layers.

Composition, process, and apparatus, for removal of water and silicon mu-oxides from chlorosilanes

DOEpatents

Tom, Glenn M.; McManus, James V.

1991-10-15

A scavenger composition having utility for removal of water and silicon mu-oxide impurities from chlorosilanes, such scavenger composition comprising: (a) a support; and (b) associated with the support, one or more compound(s) selected from the group consisting of compounds of the formula: R.sub.a-x MCl.sub.x wherein: M is a metal selected from the group consisting of the monovalent metals lithium, sodium, and potassium; the divalent metals magnesium, strontium, barium, and calcium; and the trivalent metal aluminum; R is alkyl; a is a number equal to the valency of metal M; and x is a number having a value from 0 to a, inclusive; and wherein said compound(s) of the formula R.sub.a-x MCl.sub.x have been activated for impurity-removal service by a reaction scheme selected from those of the group consisting of: (i) reaction of such compound(s) with hydrogen chloride to form a first reaction product therefrom, followed by reaction of the first reaction product with a chlorosilane of the formula: SiH.sub.4"y Cl.sub.y, wherein y is a number having a value of from 1 to 3, inclusive; and (ii) reaction of such compound(s) with a chlorosilane of the formula: SiH.sub.4-y Cl.sub.y wherein y is a number having a value of 1 to 3, inclusive. A corresponding method of making the scavenger composition, and of purifying a chlorosilane which contains oxygen and silicon mu-oxide impurities, likewise are disclosed, together with a purifier apparatus, in which a bed of the scavenger composition is disposed. The composition, purification process, and purifier apparatus of the invention have utility in purifying gaseous chlorosilanes which are employed in the semiconductor industry as silicon source reagents for forming epitaxial silicon layers.

Synthesis, crystal structures and luminescence properties of two metal carboxyphosphonates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Chaonan; Feng, Pingjing; Li, Jintang, E-mail: leejt@xmu.edu.cn

2017-05-15

Two metal carboxyphosphonates, [Co{sub 2}(OOCC{sub 5}H{sub 3}NPO{sub 3}){sub 2·}(H{sub 2}O){sub 3}] (Compound1) and Zn{sub 3}[OOCC{sub 6}H{sub 3}CH(OH)PO{sub 3}]{sub 2·}2H{sub 2}O (Compound2) were successfully synthesized under the hydrothermal reactions. In compound 1, two (Co1-NO{sub 5}) octahedra link the (CPO{sub 3}) by sharing the corner, which link the two (Co2-O{sub 6}) octahedra. From a-axis the six clusters form the layer. Each layer is linked through hydrogen bond. In compound 2, the (Zn-O{sub 4}) tetrahedron and (CPO{sub 3}) tetrahedron are corner-shared, which arrange in line. From a-axis, each line forms the columnar. The thermal and luminescence properties of these compounds were investigated. -more » Graphical abstract: The synthesis conditions of the two compounds and the crystal morphology. Compound 1 shows the layer and the compound 2 shows the pillared-layer. - Highlights: • Two new carboxyphosphonate ligands have been prepared. • Using the two ligands, two metal carboxyphosphonates have been synthesized. • The two MOFs may be candidates for fluorescent materials.« less

Solid state electrochemical current source

DOEpatents

Potanin, Alexander Arkadyevich; Vedeneev, Nikolai Ivanovich

2002-04-30

A cathode and a solid state electrochemical cell comprising said cathode, a solid anode and solid fluoride ion conducting electrolyte. The cathode comprises a metal oxide and a compound fluoride containing at least two metals with different valences. Representative compound fluorides include solid solutions of bismuth fluoride and potassium fluoride; and lead fluoride and potassium fluoride. Representative metal oxides include copper oxide, lead oxide, manganese oxide, vanadium oxide and silver oxide.

Systems for the Storage of Molecular Oxygen - A Study.

DTIC Science & Technology

1980-11-25

form adducts with certain chemical compounds . This process, which will be called chemical absorption, generally uses a transition metal coordination... compound as the absorber. The study of oxygen binding to metal complexes has become of great interest over the past three decades (21), and some...for iron, most notably cobalt (33-35) manganese (36,37) and ruthenium (38), usually to serve as model compounds for biologically important heme

Synthetic process for preparation of high surface area electroactive compounds for battery applications

DOEpatents

Evenson, Carl; Mackay, Richard

2013-07-23

A process is disclosed for the preparation of electroactive cathode compounds useful in lithium-ion batteries, comprising exothermic mixing of low-cost precursors and calcination under appropriate conditions. The exothermic step may be a spontaneous flameless combustion reaction. The disclosed process can be used to prepare any lithium metal phosphate or lithium mixed metal phosphate as a high surface area single phase compound.

Metal alkyls programmed to generate metal alkylidenes by α-H abstraction: prognosis from NMR chemical shift† †Electronic supplementary information (ESI) available: Experimental and computational details, NMR spectra, results of NMR calculations and NCS analysis, graphical representation of shielding tensors, molecular orbital diagrams of selected compounds, optimized structures for all calculated species. See DOI: 10.1039/c7sc05039a

PubMed Central

Gordon, Christopher P.; Yamamoto, Keishi; Searles, Keith; Shirase, Satoru

2018-01-01

Metal alkylidenes, which are key organometallic intermediates in reactions such as olefination or alkene and alkane metathesis, are typically generated from metal dialkyl compounds [M](CH2R)2 that show distinctively deshielded chemical shifts for their α-carbons. Experimental solid-state NMR measurements combined with DFT/ZORA calculations and a chemical shift tensor analysis reveal that this remarkable deshielding originates from an empty metal d-orbital oriented in the M–Cα–Cα′ plane, interacting with the Cα p-orbital lying in the same plane. This π-type interaction inscribes some alkylidene character into Cα that favors alkylidene generation via α-H abstraction. The extent of the deshielding and the anisotropy of the alkyl chemical shift tensors distinguishes [M](CH2R)2 compounds that form alkylidenes from those that do not, relating the reactivity to molecular orbitals of the respective molecules. The α-carbon chemical shifts and tensor orientations thus predict the reactivity of metal alkyl compounds towards alkylidene generation. PMID:29675237

Salt flux synthesis of single and bimetallic carbide nanowires

NASA Astrophysics Data System (ADS)

Leonard, Brian M.; Waetzig, Gregory R.; Clouser, Dale A.; Schmuecker, Samantha M.; Harris, Daniel P.; Stacy, John M.; Duffee, Kyle D.; Wan, Cheng

2016-07-01

Metal carbide compounds have a broad range of interesting properties and are some of the hardest and highest melting point compounds known. However, their high melting points force very high reaction temperatures and thus limit the formation of high surface area nanomaterials. To avoid the extreme synthesis temperatures commonly associated with these materials, a new salt flux technique has been employed to reduce reaction temperatures and form these materials in the nanometer regime. Additionally, the use of multiwall carbon nanotubes as a reactant further reduces the diffusion distance and provides a template for the final carbide materials. The metal carbide compounds produced through this low temperature salt flux technique maintain the nanowire morphology of the carbon nanotubes but increase in size to ˜15-20 nm diameter due to the incorporation of metal in the carbon lattice. These nano-carbides not only have nanowire like shape but also have much higher surface areas than traditionally prepared metal carbides. Finally, bimetallic carbides with composition control can be produced with this method by simply using two metal precursors in the reaction. This method provides the ability to produce nano sized metal carbide materials with size, morphology, and composition control and will allow for these compounds to be synthesized and studied in a whole new size and temperature regime.

Preparation of cermets

DOEpatents

Morgan, Chester S.

1978-01-01

Cermets are produced by the process of forming a physical mixture of a ceramic powder material with an elemental metal precursor compound and by decomposing the elemental metal precursor compound within the mixture. The decomposition step may be carried out either prior to or during a forming and densification step.

Catalytic pyrolysis of wheat bran for hydrocarbons production in the presence of zeolites and noble-metals by using TGA-FTIR method.

PubMed

Lazdovica, K; Liepina, L; Kampars, V

2016-05-01

Pyrolysis of wheat bran with or without catalysts was investigated using TGA-FTIR method in order to determine the influence of zeolite and noble metal catalysts on the evolution profile and relative yield of the volatile compounds. The addition of all catalysts decreased the volatile matter of wheat bran from 76.3% to 75.9%, 73.9%, 73.5%, 69.7% and increased the solid residue from 18.0% to 18.4%, 20.4%, 20.8%, 24.6% under the catalyst of ZSM-5, 5% Pd/C, MCM-41, and 5% Pt/C. Noble-metal catalysts had higher activity for deoxygenation of compounds containing carbonyl, carboxyl, and hydroxyl groups than zeolites. Degradation of nitrogen containing compounds atom proceeded better in presence of zeolites. Noble-metal catalysts promoted formation of aromatics and changed the profiles of evolved compounds whereas zeolites advanced formation of aliphatics and olefins. Copyright © 2016 Elsevier Ltd. All rights reserved.

A chemometrics as a powerful tool in the elucidation of the role of metals in the biosynthesis of volatile organic compounds in Hungarian thyme samples.

PubMed

Arsenijević, Jelena; Marković, Jelena; Soštarić, Ivan; Ražić, Slavica

2013-10-01

The volatile fraction of the leaves of Thymus pannonicus All. (Lamiaceae) was analyzed by headspace extraction followed by GC-FID and GC-MS analysis. The different headspace profiles were recognized, with citral and with monoterpene hydrocarbons as dominant compounds. In addition, the determination of Cr, Co, Ni, Mo, Cu, Zn, Mn, Fe, Mg, Ca, K and Na was conducted by spectroscopic techniques (FAAS, GFAAS and ICP-OES). In order to evaluate the relationship between volatile organic compounds and metals, a chemometrics approach was applied. The data obtained by analysis of the headspace and elemental content were subjected to correlation analysis, factor analysis, principal component analysis and cluster analysis. A number of significant correlations of metals with plant volatiles were found. Correlation of Zn with citral, Mn with oxygenated monoterpenes and Mg with β-bourbonene, could be explained by involvement of metals in the biosynthesis of volatile organic compounds. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Intercalation compounds and electrodes for batteries

DOEpatents

Chiang, Yet-Ming; Sadoway, Donald R.; Jang, Young-Il; Huang, Biyan

2004-09-07

This invention concerns intercalation compounds and in particular lithium intercalation compounds which have improved properties for use in batteries. Compositions of the invention include particulate metal oxide material having particles of multicomponent metal oxide, each including an oxide core of at least first and second metals in a first ratio, and each including a surface coating of metal oxide or hydroxide that does not include the first and second metals in the first ratio formed by segregation of at least one of the first and second metals from the core. The core may preferably comprise Li.sub.x M.sub.y N.sub.z O.sub.2 wherein M and N are metal atom or main group elements, x, y and z are numbers from about 0 to about 1 and y and z are such that a formal charge on M.sub.y N.sub.z portion of the compound is (4-x), and having a charging voltage of at least about 2.5V. The invention may also be characterized as a multicomponent oxide microstructure usable as a lithium intercalation material including a multiphase oxide core and a surface layer of one material, which is a component of the multiphase oxide core, that protects the underlying intercalation material from chemical dissolution or reaction. In a particular preferred example the multicomponent oxide may be an aluminum-doped lithium manganese oxide composition. Such aluminum-doped lithium manganese oxide compositions, having an orthorhombic structure, also form a part of the invention. In addition, the invention includes articles, particularly electrodes, for batteries formed from the compositions of the invention, and batteries including such electrodes. The invention further relates to a composite intercalation material comprising at least two compounds in which at least one compound has an orthorhombic structure Li.sub.x Al.sub.y Mn.sub.1-y O.sub.2, where y is nonzero, or a mixture of orthorhombic and monoclinic Li.sub.x Al.sub.y Mn.sub.1-y O.sub.2.

The use of dialdehyde starch derivatives in the phytoremediation of soils contaminated with heavy metals.

PubMed

Antonkiewicz, Jacek; Para, Andrzej

2016-01-01

Products of the reaction between dialdehyde starch and Y-NH2 compounds (e.g. semicarbazide or hydrazine) are effective ligands for metal ions. The usefulness of these derivatives was tested in the experiment, both in terms of the immobilization of heavy metal ions in soil and the potential application in phytoextraction processes. The experimental model comprised maize and the ions of such metals as: Zn(II), Pb(II), Cu(II), Cd(II), and Ni(II). The amount of maize yield, as well as heavy metal content and uptake by the aboveground parts and roots of maize, were studied during a three-year pot experiment. The results of the study indicate the significant impact of heavy metals on reduced yield and increased heavy metal content in maize. Soil-applied dialdehyde starch derivatives resulted in lower yields, particularly disemicarbazone (DASS), but in heavy metal-contaminated soils they largely limited the negative impact of these metals both on yielding and heavy metal content in plants, particularly dihydrazone (DASH). It was demonstrated that the application of dihydrazone (DASH) to a soil polluted with heavy metals boosted the uptake of Zn, Pb, Cu, and Cd from the soil, hence there is a possibility to use this compound in the phytoextraction of these metals from the soil. Decreased Ni uptake was also determined, hence the possibility of using this compound in the immobilization of this metal. The study showed that dialdehyde starch disemicarbazone was ineffective in the discussed processes.

Inorganic Nanotubes and Fullerene-like Nanoparticles at the Crossroads between Solid-State Chemistry and Nanotechnology.

PubMed

Višić, Bojana; Panchakarla, Leela Srinivas; Tenne, Reshef

2017-09-20

Inorganic nanotubes (NTs) and fullerene-like nanoparticles (NPs) of WS 2 were discovered some 25 years ago and are produced now on a commercial scale for various applications. This Perspective provides a brief description of recent progress in this scientific discipline. The conceptual evolution leading to the discovery of these NTs and NPs is briefly discussed. Subsequently, recent progress in the synthesis of such NPs from a variety of inorganic compounds with layered (2D) structure is described. In particular, we discuss the synthesis of NTs from chalcogenide- and oxide-based ternary misfit layered compounds, as well as their structure and different growth mechanisms. Next we deliberate on the mechanical, optical, electrical, and electromechanical properties, which delineate them from their bulk counterparts and also from their graphene-like analogues. Here, different experiments with individual NTs coupled with first-principles and molecular dynamics calculations demonstrate the unique physical nature of these quasi-1D nanostructures. Finally, the various applications of the fullerene-like NPs of WS 2 and NTs formed therefrom are deliberated. Foremost among the possibilities are their extensive uses as superior solid lubricants. Combined with their nontoxicity and their facile dispersion, these NTs, with an ultimate strength of about 20 GPa, are likely to find numerous applications in reinforcing polymers, adhesives, textiles, medical devices, metallic alloys, and even concrete. Other potential applications in energy-harvesting and catalysis are discussed in brief.

HAZARD ASSESSMENT OF METALS AND METAL COMPOUNDS IN TERRESTRIAL SYSTEMS

EPA Science Inventory

Metal accumulation in soil can result in adverse effects on soil biota, and may concentrate metals in food chains to levels detrimental to humans and wildlife. A SETAC Pellston Workshop entitled " Hazard Identification Approach For Metals And Inorganic Metal Substances" examined...

Spectroscopic Characterization of Aqua [ fac-Tc(CO)3]+ Complexes at High Ionic Strength.

PubMed

Chatterjee, Sayandev; Hall, Gabriel B; Engelhard, Mark H; Du, Yingge; Washton, Nancy M; Lukens, Wayne W; Lee, Sungsik; Pearce, Carolyn I; Levitskaia, Tatiana G

2018-06-18

Understanding fundamental Tc chemistry is important to both the remediation of nuclear waste and the reprocessing of nuclear fuel; however, current knowledge of the electronic structure and spectral signatures of low-valent Tc compounds significantly lags behind the remainder of the d-block elements. In particular, identification and treatment of Tc speciation in legacy nuclear waste is challenging due to the lack of reference data especially for Tc compounds in the less common oxidation states (I-VI). In an effort to establish a spectroscopic library corresponding to the relevant conditions of extremely high ionic strength typical for the legacy nuclear waste, compounds with the general formula of [ fac-Tc(CO) 3 (OH 2 ) 3- n (OH) n ] 1- n (where n = 0-3) were examined by a range of spectroscopic techniques including 99 Tc/ 13 C NMR, IR, XPS, and XAS. In the series of monomeric aqua species, stepwise hydrolysis results in the increase of the Tc metal center electron density and corresponding progressive decrease of the Tc-C bond distances, Tc electron binding energies, and carbonyl stretching frequencies in the order [ fac-Tc(CO) 3 (OH 2 ) 3 ] + > [ fac-Tc(CO) 3 (OH 2 ) 2 (OH)] > [ fac-Tc(CO) 3 (OH 2 )(OH) 2 ] - . These results correlate with established trends of the 99 Tc upfield chemical shift and carbonyl 13 C downfield chemical shift. The lone exception is [ fac-Tc(CO) 3 (OH)] 4 which exhibits a comparatively low electron density at the metal center attributed to the μ 3 -bridging nature of the - OH ligands causing less σ-donation and no π-donation. This work also reports the first observations of these compounds by XPS and [ fac-Tc(CO) 3 Cl 3 ] 2- by XAS. The unique and distinguishable spectral features of the aqua [ fac-Tc(CO) 3 ] + complexes lay the foundation for their identification in the complex aqueous matrixes.

The electronic and magnetic properties of quaternary Heusler alloy CoFeMnGe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seema, K.

2016-05-23

We present study of quaternary Heusler alloy CoFeMnGe using density functional theory. The compound is half-metallic with half-metallic gap of 0.13 eV. The total magnetic moment of this compound is 3.96 μ{sub B} which is in close agreement with Slater-Pauling rule. The effect of lattice compression and expansion shows the robustness of half-metallicity. A large value of half-metallic gap and 100% spin-polarization makes this material interesting for spin dependent applications.

A library of atomically thin metal chalcogenides.

PubMed

Zhou, Jiadong; Lin, Junhao; Huang, Xiangwei; Zhou, Yao; Chen, Yu; Xia, Juan; Wang, Hong; Xie, Yu; Yu, Huimei; Lei, Jincheng; Wu, Di; Liu, Fucai; Fu, Qundong; Zeng, Qingsheng; Hsu, Chuang-Han; Yang, Changli; Lu, Li; Yu, Ting; Shen, Zexiang; Lin, Hsin; Yakobson, Boris I; Liu, Qian; Suenaga, Kazu; Liu, Guangtong; Liu, Zheng

2018-04-01

Investigations of two-dimensional transition-metal chalcogenides (TMCs) have recently revealed interesting physical phenomena, including the quantum spin Hall effect 1,2 , valley polarization 3,4 and two-dimensional superconductivity 5 , suggesting potential applications for functional devices 6-10 . However, of the numerous compounds available, only a handful, such as Mo- and W-based TMCs, have been synthesized, typically via sulfurization 11-15 , selenization 16,17 and tellurization 18 of metals and metal compounds. Many TMCs are difficult to produce because of the high melting points of their metal and metal oxide precursors. Molten-salt-assisted methods have been used to produce ceramic powders at relatively low temperature 19 and this approach 20 was recently employed to facilitate the growth of monolayer WS 2 and WSe 2 . Here we demonstrate that molten-salt-assisted chemical vapour deposition can be broadly applied for the synthesis of a wide variety of two-dimensional (atomically thin) TMCs. We synthesized 47 compounds, including 32 binary compounds (based on the transition metals Ti, Zr, Hf, V, Nb, Ta, Mo, W, Re, Pt, Pd and Fe), 13 alloys (including 11 ternary, one quaternary and one quinary), and two heterostructured compounds. We elaborate how the salt decreases the melting point of the reactants and facilitates the formation of intermediate products, increasing the overall reaction rate. Most of the synthesized materials in our library are useful, as supported by evidence of superconductivity in our monolayer NbSe 2 and MoTe 2 samples 21,22 and of high mobilities in MoS 2 and ReS 2 . Although the quality of some of the materials still requires development, our work opens up opportunities for studying the properties and potential application of a wide variety of two-dimensional TMCs.

Organic-Inorganic Hybrid Polymers as Adsorbents for Removal of Heavy Metal Ions from Solutions: A Review

PubMed Central

Samiey, Babak; Cheng, Chil-Hung; Wu, Jiangning

2014-01-01

Over the past decades, organic-inorganic hybrid polymers have been applied in different fields, including the adsorption of pollutants from wastewater and solid-state separations. In this review, firstly, these compounds are classified. These compounds are prepared by sol-gel method, self-assembly process (mesopores), assembling of nanobuilding blocks (e.g., layered or core-shell compounds) and as interpenetrating networks and hierarchically structures. Lastly, the adsorption characteristics of heavy metals of these materials, including different kinds of functional groups, selectivity of them for heavy metals, effect of pH and synthesis conditions on adsorption capacity, are studied. PMID:28788483

Layered electrodes for lithium cells and batteries

DOEpatents

Johnson; Christopher S. , Thackeray; Michael M. , Vaughey; John T. , Kahaian; Arthur J. , Kim; Jeom-Soo

2008-04-15

Lithium metal oxide compounds of nominal formula Li.sub.2MO.sub.2, in which M represents two or more positively charged metal ions, selected predominantly and preferably from the first row of transition metals are disclosed herein. The Li.sub.2MO.sub.2 compounds have a layered-type structure, which can be used as positive electrodes for lithium electrochemical cells, or as a precursor for the in-situ electrochemical fabrication of LiMO.sub.2 electrodes. The Li.sub.2MO.sub.2 compounds of the invention may have additional functions in lithium cells, for example, as end-of-discharge indicators, or as negative electrodes for lithium cells.

The effects of heavy metal ions, phthalates and ochratoxin A on oxidation of carcinogenic aristolochic acid I causing Balkan endemic nephropathy.

PubMed

Barta, Frantisek; Levova, Katerina; Hodek, Petr; Schmeiser, Heinz H; Arlt, Volker M; Stiborova, Marie

2015-01-01

Balkan endemic nephropathy (BEN) is a chronic progressive fibrosis associated with upper urothelial carcinoma (UUC). Aetiology of BEN is still not fully explained. Although carcinogenic aristolochic acid I (AAI) was proven as the major cause of BEN/UUC, this nephropathy is considered to be multifactorial. Hence, we investigated whether other factors considered as potential causes of BEN [a mycotoxin ochratoxin A (OTA), Cd, Pb, Se and As ions and organic compounds (i.e. phthalates) released from lignite deposits in BEN areas] can influence detoxication of AAI, whose concentrations are crucial for BEN development. Oxidation of AAI to 8-hydroxyaristolochic acid I (AAIa) in the presence of Cd, Pb, Se, As ions, dibutylphthalate (DBP), butylbenzylphthalate (BBP), bis(2-ethylhexyl)phthalate (DEHP) and OTA by rat liver microsomes was determined by HPLC. Only OTA, cadmium and selenium ions, and BBP inhibited AAI oxidation by rat liver microsomes. These compounds also inhibited activities of CYP1A1 and/or CYP2C6/11 catalysing AAI demethylation in rat livers. Therefore, these CYP inhibitions can be responsible for a decrease in AAIa formation. When the combined effects of these compounds were investigated, the most efficient inhibition was caused by OTA combined with BBP and selenium ions. The results show low effects of BBP, cadmium and selenium ions, and/or their combinations on AAI detoxication. No effects were produced by the other metal ions (Pb, As) and phthalates DBP and DEHP. This finding suggests that they do not influence AAI-mediated BEN development. In contrast, OTA might influence this process, by inhibition of AAI detoxication.

Framework for Metals Risk Assessment

EPA Pesticide Factsheets

The Framework for Metals Risk Assessment is a science-based document that addresses the special attributes and behaviors of metals and metal compounds to be considered when assessing their human health and ecological risks.

Simple spectroscope used with solid state image amplifier over wide spectral range

NASA Technical Reports Server (NTRS)

Brown, R. L., Sr.

1971-01-01

Prism plus image amplifier panel provides visual image of many infrared spectral lines from carbon arc impregnated with metal compound. Different metal compounds generate various desired spectra. Panel also aligns and focuses simple spectroscopes for detecting spectral lines inside and outside visible region.

OVERVIEW OF UIN/CEC LRTAP PROTOCOLS ON POPS AND HEAVY METALS

EPA Science Inventory

The purpose of this workshop was to review the current state-of-the-science for persistent organic pollutants and heavy metal compounds, especially additional developments since the conclusion of the negotiations of the Protocols on these compounds under the Convention on Long Ra...

In silico strategies for the selection of chelating compounds with potential application in metal-promoted neurodegenerative diseases

NASA Astrophysics Data System (ADS)

Rodríguez-Rodríguez, Cristina; Rimola, Albert; Alí-Torres, Jorge; Sodupe, Mariona; González-Duarte, Pilar

2011-01-01

The development of new strategies to find commercial molecules with promising biochemical features is a main target in the field of biomedicine chemistry. In this work we present an in silico-based protocol that allows identifying commercial compounds with suitable metal coordinating and pharmacokinetic properties to act as metal-ion chelators in metal-promoted neurodegenerative diseases (MpND). Selection of the chelating ligands is done by combining quantum chemical calculations with the search of commercial compounds on different databases via virtual screening. Starting from different designed molecular frameworks, which mainly constitute the binding site, the virtual screening on databases facilitates the identification of different commercial molecules that enclose such scaffolds and, by imposing a set of chemical and pharmacokinetic filters, obey some drug-like requirements mandatory to deal with MpND. The quantum mechanical calculations are useful to gauge the chelating properties of the selected candidate molecules by determining the structure of metal complexes and evaluating their stability constants. With the proposed strategy, commercial compounds containing N and S donor atoms in the binding sites and capable to cross the BBB have been identified and their chelating properties analyzed.

Electron-Poor Polar Intermetallics: Complex Structures, Novel Clusters, and Intriguing Bonding with Pronounced Electron Delocalization.

PubMed

Lin, Qisheng; Miller, Gordon J

2018-01-16

Intermetallic compounds represent an extensive pool of candidates for energy related applications stemming from magnetic, electric, optic, caloric, and catalytic properties. The discovery of novel intermetallic compounds can enhance understanding of the chemical principles that govern structural stability and chemical bonding as well as finding new applications. Valence electron-poor polar intermetallics with valence electron concentrations (VECs) between 2.0 and 3.0 e - /atom show a plethora of unprecedented and fascinating structural motifs and bonding features. Therefore, establishing simple structure-bonding-property relationships is especially challenging for this compound class because commonly accepted valence electron counting rules are inappropriate. During our efforts to find quasicrystals and crystalline approximants by valence electron tuning near 2.0 e - /atom, we observed that compositions close to those of quasicrystals are exceptional sources for unprecedented valence electron-poor polar intermetallics, e.g., Ca 4 Au 10 In 3 containing (Au 10 In 3 ) wavy layers, Li 14.7 Mg 36.8 Cu 21.5 Ga 66 adopting a type IV clathrate framework, and Sc 4 Mg x Cu 15-x Ga 7.5 that is incommensurately modulated. In particular, exploratory syntheses of AAu 3 T (A = Ca, Sr, Ba and T = Ge, Sn) phases led to interesting bonding features for Au, such as columns, layers, and lonsdaleite-type tetrahedral frameworks. Overall, the breadth of Au-rich polar intermetallics originates, in part, from significant relativistics effect on the valence electrons of Au, effects which result in greater 6s/5d orbital mixing, a small effective metallic radius, and an enhanced Mulliken electronegativity, all leading to ultimate enhanced binding with nearly all metals including itself. Two other successful strategies to mine electron-poor polar intermetallics include lithiation and "cation-rich" phases. Along these lines, we have studied lithiated Zn-rich compounds in which structural complexity can be realized by small amounts of Li replacing Zn atoms in the parent binary compounds CaZn 2 , CaZn 3 , and CaZn 5 ; their phase formation and bonding schemes can be rationalized by Fermi surface-Brillouin zone interactions between nearly free-electron states. "Cation-rich", electron-poor polar intermetallics have emerged using rare earth metals as the electropositive ("cationic") component together metal/metalloid clusters that mimic the backbones of aromatic hydrocarbon molecules, which give evidence of extensive electronic delocalization and multicenter bonding. Thus, we can identify three distinct, valence electron-poor, polar intermetallic systems that have yielded unprecedented phases adopting novel structures containing complex clusters and intriguing bonding characteristics. In this Account, we summarize our recent specific progress in the developments of novel Au-rich BaAl 4 -type related structures, shown in the "gold-rich grid", lithiation-modulated Ca-Li-Zn phases stabilized by different bonding characteristics, and rare earth-rich polar intermetallics containing unprecedented hydrocarbon-like planar Co-Ge metal clusters and pronounced delocalized multicenter bonding. We will focus mainly on novel structural motifs, bonding analyses, and the role of valence electrons for phase stability.

Process for removing heavy metal compounds from heavy crude oil

DOEpatents

Cha, Chang Y.; Boysen, John E.; Branthaver, Jan F.

1991-01-01

A process is provided for removing heavy metal compounds from heavy crude oil by mixing the heavy crude oil with tar sand; preheating the mixture to a temperature of about 650.degree. F.; heating said mixture to up to 800.degree. F.; and separating tar sand from the light oils formed during said heating. The heavy metals removed from the heavy oils can be recovered from the spent sand for other uses.

Metal-containing and related polymers for biomedical applications.

PubMed

Yan, Yi; Zhang, Jiuyang; Ren, Lixia; Tang, Chuanbing

2016-10-07

A survey of the most recent progress in the biomedical applications of metal-containing polymers is given. Due to the unique optical, electrochemical, and magnetic properties, at least 30 different metal elements, most of them transition metals, are introduced into polymeric frameworks for interactions with biology-relevant substrates via various means. Inspired by the advance of metal-containing small molecular drugs and promoted by the great progress in polymer chemistry, metal-containing polymers have gained momentum during recent decades. According to their different applications, this review summarizes the following biomedical applications: (1) metal-containing polymers as drug delivery vehicles; (2) metal-containing polymeric drugs and biocides, including antimicrobial and antiviral agents, anticancer drugs, photodynamic therapy agents, radiotherapy agents and biocides; (3) metal-containing polymers as biosensors, and (4) metal-containing polymers in bioimaging.

Frustration across the periodic table: heterolytic cleavage of dihydrogen by metal complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bullock, R. Morris; Chambers, Geoffrey M.

2017-07-24

This Perspective examines the field of Frustrated Lewis Pairs (FLPs) in the context of transition metal mediated heterolytic cleavage of H2, with a particular emphasis on molecular complexes bearing an intramolecular Lewis base. FLPs have traditionally been associated with group compounds, yet many transition metal reactions support a broader classification of FLPs to include certain types of transition metal complexes with reactivity resembling main group based FLPs. This article surveys transition metal complexes that heterolytically cleave H2, which vary in the degree that the Lewis pairs within these systems interact. Particular attention is focused on complexes bearing a pendant aminemore » function as the base. Consideration of transition metal compounds in the context of FLPs can inspire new innovations and improvements in transition metal catalysis.« less

Uncharged positive electrode composition

DOEpatents

Kaun, Thomas D.; Vissers, Donald R.; Shimotake, Hiroshi

1977-03-08

An uncharged positive-electrode composition contains particulate lithium sulfide, another alkali metal or alkaline earth metal compound other than sulfide, e.g., lithium carbide, and a transition metal powder. The composition along with a binder, such as electrolytic salt or a thermosetting resin is applied onto an electrically conductive substrate to form a plaque. The plaque is assembled as a positive electrode within an electrochemical cell opposite to a negative electrode containing a material such as aluminum or silicon for alloying with lithium. During charging, lithium alloy is formed within the negative electrode and transition metal sulfide such as iron sulfide is produced within the positive electrode. Excess negative electrode capacity over that from the transition metal sulfide is provided due to the electrochemical reaction of the other than sulfide alkali metal or alkaline earth metal compound.

Progress of Application Researches of Porous Fiber Metals

PubMed Central

Xi, Zhengping; Zhu, Jilei; Tang, Huiping; Ao, Qingbo; Zhi, Hao; Wang, Jianyong; Li, Cheng

2011-01-01

Metal fiber porous materials with intrinsic properties of metal and functional properties of porous materials have received a great deal of attention in the fundamental research and industry applications. With developments of the preparation technologies and industrial requirements, porous fiber metals with excellent properties are developed and applied in many industry areas, e.g., sound absorption, heat transfer, energy absorption and lightweight structures. The applied research progress of the metal fiber porous materials in such application areas based on the recent work in our group was reviewed in this paper. PMID:28879952

Ionothermal synthesis and structural transformation targeted by ion exchange in metal-1,3,5-benzenetricarboxylate compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Qing-Qing; State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002; Liu, Bing

Ionothermal reactions of 1,3,5-benzenetricarboxylate acid (H{sub 3}BTC) and Ni(NO{sub 3}){sub 2}, Co(NO{sub 3}){sub 2} and Cu(NO{sub 3}){sub 2} gave two discrete 32-membered ring-like allomers, [M{sub 2}(HBTC){sub 2}(NH{sub 2}CONH{sub 2}){sub 2}(H{sub 2}O){sub 4}]·3H{sub 2}O (M=Ni(1), Co(2)) and one layered [Cu{sub 2}(BTC)Cl(H{sub 2}O){sub 4}] (3). The weak interactions in 1 can be deconstructed to some degree in ion exchange by exploring the factors of divalent and trivalent metal species, metal concentration and soaking time, which are demonstrated by PXRD and N{sub 2} absorption. Cu{sup 2+} has the highest N{sub 2} adsorbance when soaking with 1, and 1 can keep structure stable whenmore » Cu{sup 2+} below 0.16 mol L{sup −1} and the soaking time within 24d. As Cu{sup 2+} beyond 0.16 mol L{sup −1} and the soaking time beyond 24d, the structure of compound 1 starts to transform with the crystal morphology from clear pale green to opaque blue. Ionothermal reactions of compound 1 with different Cu{sup 2+} amounts obtained Ni{sup 2+}-Cu{sup 2+} hetero complexes, whose PXRD patterns are similar to that of 3 and EDS indicates Cu{sup 2+}% increases with Cu{sup 2+} additions and close to 100% as Cu{sup 2+} being 1.6 mmol. It suggests that 3 is a controlled product and Cu{sup 2+} can transform discrete compound 1 into 2D compound 3. - Graphical abstract: Three compounds were synthesized through ionothermal reactions. The weak interactions in compound 1 can be deconstructed by ion exchange and discrete compound 1 can be transformed into layered compound 3. - Highlights: • Two discrete ring-like and one layered compounds were ionothermally synthesized. • Metal species, metal concentration and soaking time deconstruct the H-bondings in 1. • 1 can be transformed to 3 through ionothermal reaction, otherwise forbidden.« less

Metal Based Synthetic Strategies and the Examination of Structure Determining Factors in Alkaline Earth Metal Compounds

NASA Astrophysics Data System (ADS)

Takahashi, Yuriko

Last decades have witnessed a large expansion of the organometallic heavier alkaline earth metal species. However, continued growth of this promising area of chemistry has been slowed by severe restrictions and limitations in viable synthetic methodologies leading to difficulties in preparing and characterizing the target compounds. There is clearly a need for the further development of synthetic methodologies and detailed structure function analysis that will promote the further advancement of organoalkaline earth metal chemistry in applications as diverse as materials chemistry and catalysis. This thesis work greatly extends the synthetic options currently available towards organoalkaline earth metal species by introducing redox transmetallation protolysis (RTP), a reaction based on the readily available Ph3Bi as a non-toxic transmetallation agent. Based on a straightforward one-pot procedure and work-up, Ph3Bi based RTP presents a powerful synthetic alternative for the facile preparation of a large variety of heavy alkaline earth metal compounds. The second part of the thesis explores the effect of secondary non covalent interactions on the coordination chemistry as well as thermal properties of a series of novel alkali, alkaline earth, rare earth as well as heterobimetallic alkali/alkaline earth fluoroalkoxides. These compounds showcase the significance of non-covalent M···F-C and agostic interactions on metal stabilization and structural features, providing critical input on ligand design for the design of advanced metal organic vapor deposition (MOCVD) precursor materials. This work also showcases the impact of M···F-C interactions over M---co-ligand coordination, a critical precursor design element as well.

IRIS TOXICOLOGICAL REVIEW AND SUMMARY DOCUMENTS FOR CERIUM OXIDE (STABLE) AND COMPOUNDS

EPA Science Inventory

Cerium is a member of the lanthanoid series of rare earth metals. It is also the most abundant and most reactive of the rare earth metals. Cerium oxidizes at room temperature and forms a variety of salt compounds including oxides, hydroxides, sulfates and chlorides. Cerium is ...

Production of pure metals

NASA Technical Reports Server (NTRS)

Philipp, W. H.; Marsik, S. J.; May, C. E. (Inventor)

1974-01-01

A process for depositing elements by irradiating liquids is reported. Ultra pure elements are precipitated from aqueous solutions or suspensions of compounds. A solution of a salt of a metal to be prepared is irradiated, and the insoluble reaction product settles out. Some chemical compounds may also be prepared in this manner.

Radionuclides, Trace Metals, and Organic Compounds in Shells of Native Freshwater Mussels Along the Hanford Reach of the Columbia River: 6000 Years Before Present to Current Times

DOE Office of Scientific and Technical Information (OSTI.GOV)

B. L. Tiller; T. E. Marceau

2006-01-25

This report documents concentrations of radionuclides, trace metals, and semivolatile organic compounds measured in shell samples of the western pearl shell mussel collected along the Hanford Reach of the Columbia River.

Dual mechanochemical immobilization of heavy metals and decomposition of halogenated compounds in automobile shredder residue using a nano-sized metallic calcium reagent.

PubMed

Mallampati, Srinivasa Reddy; Lee, Byoung Ho; Mitoma, Yoshiharu; Simion, Cristian

2016-11-01

Simultaneous immobilization of heavy metals and decomposition of halogenated organic compounds in different fractions of automobile shredder residue (ASR) were achieved with a nano-sized metallic calcium through a 60-min ball milling treatment. Heavy metal (HM) immobilization and chlorinated/brominated compound (CBC) decomposition efficiencies both reached 90-100 %, after ball milling with nanometallic calcium/calcium oxide (Ca/CaO) dispersion, regardless of ASR particle size (1.0, 0.45-1.0, and 0.250 mm). Concentrations of leachable HMs substantially decreased to a level lower than the regulatory standard limits (Co and Cd 0.3 mg L -1 ; Cr 1.5 mg L -1 ; Fe, Pb, and Zn 3.0 mg L -1 ; Mn and Ni 1 mg L -1 ) proposed by the Korean hazardous waste elution standard regulatory threshold. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) element maps/spectra showed that while the amounts of HMs and CBCs detectable in ASR significantly decreased, the calcium mass percentage increased. X-ray powder diffraction (XRD) patterns indicate that the main fraction of enclosed/bound materials on ASR includes Ca-associated crystalline complexes that remarkably inhibit HM desorption and simultaneously transform dangerous CBCs into harmless compounds. The use of a nanometallic Ca/CaO mixture in a mechanochemical process to treat hazardous ASR (dry conditions) is an innovative approach to remediate cross-contaminated residues with heavy metals and halogenated compounds.

Antimicrobial resistance and its association with tolerance to heavy metals in agriculture production.

PubMed

Yu, Zhongyi; Gunn, Lynda; Wall, Patrick; Fanning, Séamus

2017-06-01

Antimicrobial resistance is a recognized public health challenge that since its emergence limits the therapeutic options available to veterinarians and clinicians alike, when treatment is warranted. This development is further compounded by the paucity of new antibiotics. The agri-food industry benefits from the availability of antimicrobial compounds for food-animal production and crop protection. Nonetheless, their improper use can result in the selection for bacteria that are phenotypically resistant to these compounds. Another class of agents used in agriculture includes various cationic metals that can be included in animal diets as nutritional supplements or spread on pastures to support crop growth and protection. Heavy metals, in particular, are giving rise to concerns among public health professionals, as they can persist in the environment remaining stable for prolonged periods. Moreover, bacteria can also exhibit resistance to these chemical elements and the genes encoding this phenotype can be physically localized to plasmids that may also contain one or more antimicrobial resistance-encoding gene(s). This paper reviews our current understanding of the role that bacteria play in expressing resistance to heavy metals. It will describe how heavy metals are used in agri-food production, and explore evidence available to link resistance to heavy metals and antimicrobial compounds. In addition, possible solutions to reduce the impact of heavy metal resistance are also discussed, including using organic minerals and reducing the level of trace minerals in animal feed rations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Removal of cyanide compounds from coking wastewater by ferrous sulfate: Improvement of biodegradability.

PubMed

Yu, Xubiao; Xu, Ronghua; Wei, Chaohai; Wu, Haizhen

2016-01-25

The effect of ferrous sulfate (FeSO4) treatment on the removal of cyanide compounds and the improvement of biodegradability of coking wastewater were investigated by varying Fe:TCN molar ratios. Results suggested that the reaction between FeSO4 and coking wastewater was a two-step process. At the first step, i.e., 0≤Fe:TCN≤1.0, the reaction mechanisms were dominated by the precipitation of FeS, the complexation of CN(-), and the coagulation of organic compounds. The COD of coking wastewater decreased from 3748.1 mg/L to 3450.2 mg/L, but BOD5:COD (B/C) was improved from 0.30 to 0.51. At the second step, i.e., 1.0

Mini-review: Inhibition of biofouling by marine microorganisms.

PubMed

Dobretsov, Sergey; Abed, Raeid M M; Teplitski, Max

2013-01-01

Any natural or artificial substratum exposed to seawater is quickly fouled by marine microorganisms and later by macrofouling species. Microfouling organisms on the surface of a substratum form heterogenic biofilms, which are composed of multiple species of heterotrophic bacteria, cyanobacteria, diatoms, protozoa and fungi. Biofilms on artificial structures create serious problems for industries worldwide, with effects including an increase in drag force and metal corrosion as well as a reduction in heat transfer efficiency. Additionally, microorganisms produce chemical compounds that may induce or inhibit settlement and growth of other fouling organisms. Since the last review by the first author on inhibition of biofouling by marine microbes in 2006, significant progress has been made in the field. Several antimicrobial, antialgal and antilarval compounds have been isolated from heterotrophic marine bacteria, cyanobacteria and fungi. Some of these compounds have multiple bioactivities. Microorganisms are able to disrupt biofilms by inhibition of bacterial signalling and production of enzymes that degrade bacterial signals and polymers. Epibiotic microorganisms associated with marine algae and invertebrates have a high antifouling (AF) potential, which can be used to solve biofouling problems in industry. However, more information about the production of AF compounds by marine microorganisms in situ and their mechanisms of action needs to be obtained. This review focuses on the AF activity of marine heterotrophic bacteria, cyanobacteria and fungi and covers publications from 2006 up to the end of 2012.

Controlled thermal decomposition of NaSi to derive silicon clathrate compounds

NASA Astrophysics Data System (ADS)

Horie, Hiro-omi; Kikudome, Takashi; Teramura, Kyosuke; Yamanaka, Shoji

2009-01-01

Formation conditions of two types of sodium containing silicon clathrate compounds were determined by the controlled thermal decomposition of sodium monosilicide NaSi under vacuum. The decomposition began at 360 °C. Much higher decomposition temperatures and the presence of sodium metal vapor were favorable for the formation of type I clathrate compound Na 8Si 46. Type II clathrate compound Na xSi 136 was obtained as a single phase at a decomposition temperature <440 °C under the condition without sodium metal vapor. The type I clathrate compound was decomposed to crystalline Si above 520 °C. The type II clathrate compound was thermally more stable, and retained at least up to 550 °C in vacuum.

Synthesis, characterization, MCD spectroscopy, and TD-DFT calculations of copper-metalated nonperipherally substituted octaoctyl derivatives of tetrabenzotriazaporphyrin, cis- and trans-tetrabenzodiazaporphyrin, tetrabenzomonoazaporphyrin, and tetrabenzoporphyrin.

PubMed

Mack, John; Sosa-Vargas, Lydia; Coles, Simon J; Tizzard, Graham J; Chambrier, Isabelle; Cammidge, Andrew N; Cook, Michael J; Kobayashi, Nagao

2012-12-03

Synthesis of the title compounds has been achieved through refinement of a recently reported synthetic protocol whereby varying equivalents of MeMgBr are reacted with 1,4-dioctylphthalonitrile to produce mixtures favoring specific hybrid structures. The initially formed magnesium-metalated compounds are obtained as pure materials and include, for the first time, both isomers (cis and trans) of tetrabenzodiazaporphyrin. The compounds were demetalated to the metal-free analogues, which were then converted into the copper-metalated derivatives. The X-ray structure of the copper tetrabenzotriazaporphyrin derivative is reported. The metal-free and copper-metalated macrocycles exhibit columnar mesophase behavior, and it is found that the mesophase stability is unexpectedly reduced in the diazaporphyrin derivatives compared to the rest of the series. The results of time-dependent density functional theory calculations for the copper complexes are compared to the observed optical properties. Michl's perimeter model was used as a conceptual framework for analyzing the magnetic circular dichroism spectral data, which predicted and accounted for trends in the observed experimental spectra.

A motif for infinite metal atom wires.

PubMed

Yin, Xi; Warren, Steven A; Pan, Yung-Tin; Tsao, Kai-Chieh; Gray, Danielle L; Bertke, Jeffery; Yang, Hong

2014-12-15

A new motif for infinite metal atom wires with tunable compositions and properties is developed based on the connection between metal paddlewheel and square planar complex moieties. Two infinite Pd chain compounds, [Pd4(CO)4(OAc)4Pd(acac)2] 1 and [Pd4(CO)4(TFA)4Pd(acac)2] 2, and an infinite Pd-Pt heterometallic chain compound, [Pd4(CO)4(OAc)4Pt(acac)2] 3, are identified by single-crystal X-ray diffraction analysis. In these new structures, the paddlewheel moiety is a Pd four-membered ring coordinated by bridging carboxylic ligands and μ2 carbonyl ligands. The planar moiety is either Pd(acac)2 or Pt(acac)2 (acac = acetylacetonate). These moieties are connected by metallophilic interactions. The results showed that these one-dimensional metal wire compounds have photoluminescent properties that are tunable by changing ligands and metal ions. 3 can also serve as a single source precursor for making Pd4Pt bimetallic nanostructures with precise control of metal composition. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Computer predictions on Rh-based double perovskites with unusual electronic and magnetic properties

NASA Astrophysics Data System (ADS)

Halder, Anita; Nafday, Dhani; Sanyal, Prabuddha; Saha-Dasgupta, Tanusri

2018-03-01

In search for new magnetic materials, we make computer prediction of structural, electronic and magnetic properties of yet-to-be synthesized Rh-based double perovskite compounds, Sr(Ca)2BRhO6 (B=Cr, Mn, Fe). We use combination of evolutionary algorithm, density functional theory, and statistical-mechanical tool for this purpose. We find that the unusual valence of Rh5+ may be stabilized in these compounds through formation of oxygen ligand hole. Interestingly, while the Cr-Rh and Mn-Rh compounds are predicted to be ferromagnetic half-metals, the Fe-Rh compounds are found to be rare examples of antiferromagnetic and metallic transition-metal oxide with three-dimensional electronic structure. The computed magnetic transition temperatures of the predicted compounds, obtained from finite temperature Monte Carlo study of the first principles-derived model Hamiltonian, are found to be reasonably high. The prediction of favorable growth condition of the compounds, reported in our study, obtained through extensive thermodynamic analysis should be useful for future synthesize of this interesting class of materials with intriguing properties.

Corrosion protective coating for metallic materials

DOEpatents

Buchheit, Rudolph G.; Martinez, Michael A.

1998-01-01

Corrosion protective coatings for metallic materials, particularly aluminum and aluminum alloys, produced with simple, low-cost equipment and materials other than toxic metals or metal salts, or metal cyanides. The metallic material is cleaned, degreased, and deoxidized, the surface is converted to a substantially alkaline condition, and the surface is chemically sealed with inorganic metal compounds.

Key hydride vibrational modes in [NiFe] hydrogenase model compounds studied by resonance Raman spectroscopy and density functional calculations.

PubMed

Shafaat, Hannah S; Weber, Katharina; Petrenko, Taras; Neese, Frank; Lubitz, Wolfgang

2012-11-05

Hydrogenase proteins catalyze the reversible conversion of molecular hydrogen to protons and electrons. While many enzymatic states of the [NiFe] hydrogenase have been studied extensively, there are multiple catalytically relevant EPR-silent states that remain poorly characterized. Analysis of model compounds using new spectroscopic techniques can provide a framework for the study of these elusive states within the protein. We obtained optical absorption and resonance Raman (RR) spectra of (dppe)Ni(μ-pdt)Fe(CO)(3) and [(dppe)Ni(μ-pdt)(μ-H)Fe(CO)(3)][BF(4)], which are structural and functional model compounds for the EPR-silent Ni-SI and Ni-R states of the [NiFe] hydrogenase active site. The studies presented here use RR spectroscopy to probe vibrational modes of the active site, including metal-hydride stretching vibrations along with bridging ligand-metal and Fe-CO bending vibrations, with isotopic substitution used to identify key metal-hydride modes. The metal-hydride vibrations are essentially uncoupled and represent isolated, localized stretching modes; the iron-hydride vibration occurs at 1530 cm(-1), while the nickel-hydride vibration is observed at 945 cm(-1). The significant discrepancy between the metal-hydride vibrational frequencies reflects the slight asymmetry in the metal-hydride bond lengths. Additionally, time-dependent density functional theory (TD-DFT) calculations were carried out to obtain theoretical RR spectra of these compounds. On the basis of the detailed comparison of theory and experiment, the dominant electronic transitions and significant normal modes probed in the RR experiments were assigned; the primary transitions in the visible wavelengths represent metal-to-metal and metal-to-ligand charge transfer bands. Inherent properties of metal-hydride vibrational modes in resonance Raman spectra and DFT calculations are discussed together with the prospects of observing such vibrational modes in metal-hydride-containing proteins. Such a combined theoretical and experimental approach may be valuable for characterization of analogous redox states in the [NiFe] hydrogenases.

Synthesis and characterization of boric acid mediated metal-organic frameworks based on trimesic acid and terephthalic acid

NASA Astrophysics Data System (ADS)

Ozer, Demet; Köse, Dursun A.; Şahin, Onur; Oztas, Nursen Altuntas

2017-08-01

The new metal-organic framework materials based on boric acid reported herein. Sodium and boron containing metal-organic frameworks were synthesized by one-pot self-assembly reaction in the presence of trimesic acid and terephthalic acid in water/ethanol solution. Boric acid is a relatively cheap boron source and boric acid mediated metal-organic framework prepared mild conditions compared to the other boron source based metal-organic framework. The synthesized compounds were characterized by FT-IR, p-XRD, TGA/DTA, elemental analysis, 13C-MAS NMR, 11B-NMR and single crystal measurements. The molecular formulas of compounds were estimated as C18H33B2Na5O28 and C8H24B2Na2O17 according to the structural analysis. The obtained complexes were thermally stable. Surface properties of inorganic polymer complexes were investigated by BET analyses and hydrogen storage properties of compound were also calculated.

Plasmachemical synthesis and evaluation of the thermal conductivity of metal-oxide compounds "Molybdenum-uranium dioxide"

NASA Astrophysics Data System (ADS)

Kotelnikova, Alexandra A.; Karengin, Alexander G.; Mendoza, Orlando

2018-03-01

The article represents possibility to apply oxidative and reducing plasma for plasma-chemical synthesis of metal-oxide compounds «Mo‒UO2» from water-salt mixtures «molybdic acid‒uranyl nitrate» and «molybdic acid‒ uranyl acetate». The composition of water-salt mixture was calculated and the conditions ensuring plasma-chemical synthesis of «Mo‒UO2» compounds were determined. Calculations were carried out at atmospheric pressure over a wide range of temperatures (300-4000 K), with the use of various plasma coolants (air, hydrogen). The heat conductivity coefficients of metal-oxide compounds «Mo‒UO2» consisting of continuous component (molybdenum matrix) are calculated. Inclusions from ceramics in the form of uranium dioxide were ordered in the matrix. Particular attention is paid to methods for calculating the coefficients of thermal conductivity of these compounds with the use of different models. Calculated results were compared with the experimental data.

In situ formation of coal gasification catalysts from low cost alkali metal salts

DOEpatents

Wood, Bernard J.; Brittain, Robert D.; Sancier, Kenneth M.

1985-01-01

A carbonaceous material, such as crushed coal, is admixed or impregnated with an inexpensive alkali metal compound, such as sodium chloride, and then pretreated with a stream containing steam at a temperature of 350.degree. to 650.degree. C. to enhance the catalytic activity of the mixture in a subsequent gasification of the mixture. The treatment may result in the transformation of the alkali metal compound into another, more catalytically active, form.

Metals, Molecules, Life and Death

DOE Office of Scientific and Technical Information (OSTI.GOV)

George, Graham

2004-08-31

In our normal everyday lives we are exposed to an incredibly complex chemical soup consisting of an enormous variety of different chemical compounds. Many of these compounds contain metal atoms which, once inside us, can either fulfill roles that are essential to health, or act as poisons. Studies at SLAC's Stanford Synchrotron Radiation Laboratory (SSRL) reveal the molecular details of metals in living systems; how they interact with one another, how they confer beneficial properties, and how they act as poisons.

Method for carbon dioxide splitting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, James E.; Diver, Jr., Richard B.; Siegel, Nathan P.

A method for splitting carbon dioxide via a two-step metal oxide thermochemical cycle by heating a metal oxide compound selected from an iron oxide material of the general formula A.sub.xFe.sub.3-xO.sub.4, where 0.ltoreq.x.ltoreq.1 and A is a metal selected from Mg, Cu, Zn, Ni, Co, and Mn, or a ceria oxide compound of the general formula M.sub.aCe.sub.bO.sub.c, where 0

Structural stability and electronic structure of transition metal compound: HfN

NASA Astrophysics Data System (ADS)

Sarwan, Madhu; Shukoor, V. Abdul; Singh, Sadhna

2018-05-01

The structural stability of transition metal nitride (HfN) has been investigated using density functional theory (DFT) with the help of Quantum-espresso codes. Our calculations confirm that the hafnium nitride (HfN) is stable in zinc-blende (B3) and rock-salt (B1) type structure. We have also reported the structural and electronic properties of HfN compound. These structural properties have been compared with experimental and theoretical data available on this compound.

Mechanical alloying of a hydrogenation catalyst used for the remediation of contaminated compounds

NASA Technical Reports Server (NTRS)

Quinn, Jacqueline W. (Inventor); Geiger, Cherie L. (Inventor); Aitken, Brian S. (Inventor); Clausen, Christian A. (Inventor)

2012-01-01

A hydrogenation catalyst including a base material coated with a catalytic metal is made using mechanical milling techniques. The hydrogenation catalysts are used as an excellent catalyst for the dehalogenation of contaminated compounds and the remediation of other industrial compounds. Preferably, the hydrogenation catalyst is a bimetallic particle including zero-valent metal particles coated with a catalytic material. The mechanical milling technique is simpler and cheaper than previously used methods for producing hydrogenation catalysts.

Mechanical alloying of a hydrogenation catalyst used for the remediation of contaminated compounds

NASA Technical Reports Server (NTRS)

Quinn, Jacqueline W. (Inventor); Aitken, Brian S. (Inventor); Clausen, Christian A. (Inventor); Geiger, Cherie L. (Inventor)

2010-01-01

A hydrogenation catalyst including a base material coated with a catalytic metal is made using mechanical milling techniques. The hydrogenation catalysts are used as an excellent catalyst for the dehalogenation of contaminated compounds and the remediation of other industrial compounds. Preferably, the hydrogenation catalyst is a bimetallic particle including zero-valent metal particles coated with a catalytic material. The mechanical milling technique is simpler and cheaper than previously used methods for producing hydrogenation catalysts.

Cumulative Significance of Hyporheic Exchange and Biogeochemical Processing in River Networks

NASA Astrophysics Data System (ADS)

Harvey, J. W.; Gomez-Velez, J. D.

2014-12-01

Biogeochemical reactions in rivers that decrease excessive loads of nutrients, metals, organic compounds, etc. are enhanced by hydrologic interactions with microbially and geochemically active sediments of the hyporheic zone. The significance of reactions in individual hyporheic flow paths has been shown to be controlled by the contact time between river water and sediment and the intrinsic reaction rate in the sediment. However, little is known about how the cumulative effects of hyporheic processing in large river basins. We used the river network model NEXSS (Gomez-Velez and Harvey, submitted) to simulate hyporheic exchange through synthetic river networks based on the best available models of network topology, hydraulic geometry and scaling of geomorphic features, grain size, hydraulic conductivity, and intrinsic reaction rates of nutrients and metals in river sediment. The dimensionless reaction significance factor, RSF (Harvey et al., 2013) was used to quantify the cumulative removal fraction of a reactive solute by hyporheic processing. SF scales reaction progress in a single pass through the hyporheic zone with the proportion of stream discharge passing through the hyporheic zone for a specified distance. Reaction progress is optimal where the intrinsic reaction timescale in sediment matches the residence time of hyporheic flow and is less efficient in longer residence time hyporheic flow as a result of the decreasing proportion of river flow that is processed by longer residence time hyporheic flow paths. In contrast, higher fluxes through short residence time hyporheic flow paths may be inefficient because of the repeated surface-subsurface exchanges required to complete the reaction. Using NEXSS we found that reaction efficiency may be high in both small streams and large rivers, although for different reasons. In small streams reaction progress generally is dominated by faster pathways of vertical exchange beneath submerged bedforms. Slower exchange beneath meandering river banks mainly has importance only in large rivers. For solutes entering networks in proportion to water inputs it is the lower order streams that tend to dominate cumulative reaction progress.

Multi-component intermetallic electrodes for lithium batteries

DOEpatents

Thackeray, Michael M; Trahey, Lynn; Vaughey, John T

2015-03-10

Multi-component intermetallic negative electrodes prepared by electrochemical deposition for non-aqueous lithium cells and batteries are disclosed. More specifically, the invention relates to composite intermetallic electrodes comprising two or more compounds containing metallic or metaloid elements, at least one element of which can react with lithium to form binary, ternary, quaternary or higher order compounds, these compounds being in combination with one or more other metals that are essentially inactive toward lithium and act predominantly, but not necessarily exclusively, to the electronic conductivity of, and as current collection agent for, the electrode. The invention relates more specifically to negative electrode materials that provide an operating potential between 0.05 and 2.0 V vs. metallic lithium.

How Specific Microbial Communities Benefit the Oil Industry: Biorefining and Bioprocessing for Upgrading Petroleum Oil

NASA Astrophysics Data System (ADS)

Singh, Ajay

Recent advances in molecular biology of microbes have made possible in exploring and engineering improved biocatalysts (microbes and enzymes) suitable for the oil biorefining and recovery processes (Monticello, 2000; Van Hamme et al., 2003; Kilbane, 2006). Crude oil contains about 0.05-5% sulphur, 0.5-2.1% nitrogen and heavy metals such as nickel and vanadium associated with the asphaltene fraction. High temperature- and pressure-requiring expensive hydrotreatment processes are generally used to remove sulphur and nitrogen compounds from petroleum. Biorefining processes to improve oil quality have gained lots of interest and made a significant progress in the last two decades (Le Borgne and Quintero, 2003) and is the focus of this chapter.

Lithography With Metallo-Organic Resists

NASA Astrophysics Data System (ADS)

Pastor, A. C.; Pastor, R. C.; Braunstein, M.; Tangonan, G. L.

1981-02-01

Photolithography with metallo-organic resists is a relatively new addition to photo-engraving technology, and involves the chemical incorporation of inorganic constituents into photopolymerizable organic compounds, so that the photoresist functions not merely as a masking material, as in conventional photolithography, but also as the mass transference vehicle itself. The deposition of thin structured films of metal oxides with this method has been accomplished, the metal-doped resist in each case being the metal acrylate in acrylic acid, except in those cases where the metal acrylate was insoluble. Polymerization was effected with uv irradiation. The criteria for depositing other classes of inorganic compounds are outlined.

Clean process to destroy arsenic-containing organic compounds with recovery of arsenic

DOEpatents

Upadhye, R.S.; Wang, F.T.

1996-08-13

A reduction method is provided for the treatment of arsenic-containing organic compounds with simultaneous recovery of pure arsenic. Arsenic-containing organic compounds include pesticides, herbicides, and chemical warfare agents such as Lewisite. The arsenic-containing compound is decomposed using a reducing agent. Arsine gas may be formed directly by using a hydrogen-rich reducing agent, or a metal arsenide may be formed using a pure metal reducing agent. In the latter case, the arsenide is reacted with an acid to form arsine gas. In either case, the arsine gas is then reduced to elemental arsenic. 1 fig.

Clean process to destroy arsenic-containing organic compounds with recovery of arsenic

DOEpatents

Upadhye, Ravindra S.; Wang, Francis T.

1996-01-01

A reduction method is provided for the treatment of arsenic-containing organic compounds with simultaneous recovery of pure arsenic. Arsenic-containing organic compounds include pesticides, herbicides, and chemical warfare agents such as Lewisite. The arsenic-containing compound is decomposed using a reducing agent. Arsine gas may be formed directly by using a hydrogen-rich reducing agent, or a metal arsenide may be formed using a pure metal reducing agent. In the latter case, the arsenide is reacted with an acid to form arsine gas. In either case, the arsine gas is then reduced to elemental arsenic.

Frustration across the periodic table: heterolytic cleavage of dihydrogen by metal complexes.

PubMed

Bullock, R Morris; Chambers, Geoffrey M

2017-08-28

This perspective examines frustrated Lewis pairs (FLPs) in the context of heterolytic cleavage of H 2 by transition metal complexes, with an emphasis on molecular complexes bearing an intramolecular Lewis base. FLPs have traditionally been associated with main group compounds, yet many reactions of transition metal complexes support a broader classification of FLPs that includes certain types of transition metal complexes with reactivity resembling main group-based FLPs. This article surveys transition metal complexes that heterolytically cleave H 2 , which vary in the degree that the Lewis pairs within these systems interact. Many of the examples include complexes bearing a pendant amine functioning as the base with the metal functioning as the hydride acceptor. Consideration of transition metal compounds in the context of FLPs can inspire new innovations and improvements in transition metal catalysis.This article is part of the themed issue 'Frustrated Lewis pair chemistry'. © 2017 The Author(s).

Extracting metal ions with diphosphonic acid, or derivative thereof

DOEpatents

Horwitz, Earl P.; Gatrone, Ralph C.; Nash, Kenneth L.

1994-01-01

Thermodynamically-unstable complexing agents which are diphosphonic acids and diphosphonic acid derivatives (or sulphur containing analogs), like carboxyhydroxymethanediphosphonic acid and vinylidene-1,1-diphosphonic acid, are capable of complexing with metal ions, and especially metal ions in the II, III, IV, V and VI oxidation states, to form stable, water-soluble metal ion complexes in moderately alkaline to highly-acidic media. However, the complexing agents can be decomposed, under mild conditions, into non-organic compounds which, for many purposes are environmentally-nondamaging compounds thereby degrading the complex and releasing the metal ion for disposal or recovery. Uses for such complexing agents as well as methods for their manufacture are also described.

Extracting metal ions with diphosphonic acid, or derivative thereof

DOEpatents

Horwitz, E.P.; Gatrone, R.C.; Nash, K.L.

1994-07-26

Thermodynamically-unstable complexing agents which are diphosphonic acids and diphosphonic acid derivatives (or sulfur containing analogs), like carboxyhydroxymethanediphosphonic acid and vinylidene-1,1-diphosphonic acid, are capable of complexing with metal ions, and especially metal ions in the II, III, IV, V and VI oxidation states, to form stable, water-soluble metal ion complexes in moderately alkaline to highly-acidic media. However, the complexing agents can be decomposed, under mild conditions, into non-organic compounds which, for many purposes are environmentally-nondamaging compounds thereby degrading the complex and releasing the metal ion for disposal or recovery. Uses for such complexing agents as well as methods for their manufacture are also described. 1 fig.

Selective retention of basic compounds by metal aquo-ion affinity chromatography.

PubMed

Asakawa, Yoshiki; Yamamoto, Eiichi; Asakawa, Naoki

2014-10-01

A novel metal aquo-ion affinity chromatography has been developed for the analysis of basic compounds using heat-treated silica gel containing hydrated metal cations (metal aquo-ions) as the packing material. The packing materials of the metal aquo-ion affinity chromatography were prepared by the immobilization of a single metal component such as Fe(III), Al(III), Ag(I), and Ni(II) on silica gel followed by extensive heat treatment. The immobilized metals form aquo-ions to present cation-exchange ability for basic analytes and the cation-exchange ability for basic analytes depends on pKa of the immobilized metal species. In the present study, to evaluate the retention characteristics of metal aquo-ion affinity chromatography, the on-line solid-phase extraction of drugs was investigated. Obtained data clearly evidence the selective retention capability of metal aquo-ion affinity chromatography for basic analytes with sufficient capacity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of the public health risks associated with semivolatile metal and dioxin emissions from hazardous waste incinerators.

PubMed Central

Sedman, R M; Esparza, J R

1991-01-01

The public health impacts associated with stack emissions from hazardous waste incinerators have become a major concern in recent years. Most evaluations of incinerator stack emissions have focused on three classes of compounds: metals, semivolatile, and volatile compounds. These investigations have been complicated by the difficulty and expense of analyzing the emissions and the limited amount of toxicity information for many of the compounds that have been detected. The results of over 20 trial burns at hazardous waste incinerators were assembled in an attempt to determine which compounds may pose a significant threat to the public health. The risks associated with semivolatile emissions were found to be inconsequential, although further study of dioxins and dibenzofurans emissions appears to be warranted. The risk associated with the emission of cadmium and perhaps chromium (VI) may pose a significant risk to public health at certain facilities. Controls on waste feed or air pollution control devices should be employed to reduce the emission of these metals. Any monitoring of metal emissions from hazardous waste incinerators should focus on cadmium and chromium (VI). PMID:1954929

Photo-voltaic power generating means and methods

DOEpatents

Kroger, Ferdinand A.; Rod, Robert L.; Panicker, M. P. Ramachandra

1983-08-23

A photo-voltaic power cell based on a photoelectric semiconductor compound and the method of using and making the same. The semiconductor compound in the photo-voltaic power cell of the present invention can be electrolytically formed at a cathode in an electrolytic solution by causing discharge or decomposition of ions or molecules of a non-metallic component with deposition of the non-metallic component on the cathode and simultaneously providing ions of a metal component which discharge and combine with the non-metallic component at the cathode thereby forming the semiconductor compound film material thereon. By stoichiometrically adjusting the amounts of the components, or otherwise by introducing dopants into the desired amounts, an N-type layer can be formed and thereafter a P-type layer can be formed with a junction therebetween. The invention is effective in producing homojunction semiconductor materials and heterojunction semiconductor materials. The present invention also provides a method of using three electrodes in order to form the semiconductor compound material on one of these electrodes. Various examples are given for manufacturing different photo-voltaic cells in accordance with the present invention.

Photo-voltaic power generating means and methods

DOEpatents

Kroger, Ferdinand A.; Rod, Robert L.; Panicker, Ramachandra M. P.; Knaster, Mark B.

1984-01-10

A photo-voltaic power cell based on a photoelectric semiconductor compound and the method of using and making the same. The semiconductor compound in the photo-voltaic power cell of the present invention can be electrolytically formed at a cathode in an electrolytic solution by causing discharge or decomposition of ions or molecules of a non-metallic component with deposition of the non-metallic component on the cathode and simultaneously providing ions of a metal component which discharge and combine with the non-metallic component at the cathode thereby forming the semiconductor compound film material thereon. By stoichiometrically adjusting the amounts of the components, or otherwise by introducing dopants into the desired amounts, an N-type layer can be formed and thereafter a P-type layer can be formed with a junction therebetween. The invention is effective in producing homojunction semiconductor materials and heterojunction semiconductor materials. The present invention also provides a method of using three electrodes in order to form the semiconductor compound material on one of these electrodes. Various examples are given for manufacturing different photo-voltaic cells in accordance with the present invention.

Magnetism and structure of a half-metallic Heusler compound Co-Mn-Cr-Si

NASA Astrophysics Data System (ADS)

Huh, Yung; Joshi, Swarangi; Jain, Sanmati; Pathak, Ojas; Kharel, Parashu

Half metallic ferromagnetic Heusler compounds have a potential in the development of spintronic devices for its high spin polarization at the Fermi level and lattice structure compatibility. Heusler compounds based on cobalt are considered a good candidate for room temperature half-metals due to their high Curie temperature. Co2CrSi is one of such predicted half-metal, but it is meta-stable and difficult to synthesize in the desired crystal structure. We have successfully synthesized a Heusler compound Co2Mn0.5Cr0.5Si by using arc melting and rapid quenching followed by thermal treatment under high vacuum to control any parasitic contamination. Crystal X-ray diffraction pattern shows the samples crystallize in a cubic Heusler structure with some degrees of structural disorder. Curie temperatures of the prepared samples are observed well beyond room temperature near 900 K. Magnetic anomalies present in as-prepared samples are cleared, and its magnetic properties are improved by thermal treatment. This research is supported by Academic and Scholarly Excellence Funds, and Research/Scholarship Support Fund, South Dakota State University.

Theory of electron--photon scattering effects in metals. Progress report, December 1, 1976--November 30, 1977

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrence, W.E.

1977-01-01

The general areas in which the investigations were carried out are transport properties and quasiparticle lifetimes in normal metals and superconductors. The more specific research projects upon which progress is reported are (a) the calculation of order parameter relaxation times in aluminum, (b) transport coefficients of the noble metals (emphasizing deviations from Matthiessen's rule), (c) variational transport calculations for a superconductor, (d) some general results on quasiparticle relaxation time anisotropy in polyvalent metals, and (e) a clarification of the roles of electron-electron and electron-phonon scattering in somple metals at low temperatures.

Corrosion protective coating for metallic materials

DOEpatents

Buchheit, R.G.; Martinez, M.A.

1998-05-26

Corrosion protective coatings for metallic materials, particularly aluminum and aluminum alloys, produced with simple, low-cost equipment and materials other than toxic metals or metal salts, or metal cyanides is disclosed. The metallic material is cleaned, degreased, and deoxidized, the surface is converted to a substantially alkaline condition, and the surface is chemically sealed with inorganic metal compounds. 1 fig.

Mott insulator-to-metal transition in yttrium-doped CaIrO₃.

PubMed

Gunasekera, J; Chen, Y; Kremenak, J W; Miceli, P F; Singh, D K

2015-02-11

We report on the study of insulator-to-metal transition in post-perovskite compound CaIrO3. It is discovered that a gradual chemical substitution of calcium by yttrium leads to the onset of strong metallic behavior in this compound. This observation is in stark contrast to BaIrO3, which preserves its Mott insulating behavior despite excess of the charge carriers due to yttrium doping. Magnetic measurements reveal that both compounds tend to exhibit magnetic character irrespective of the chemical substitution of Ca or Ba. We analyze these unusual observations in light of recent researches that suggest that CaIrO3 does not necessarily possess j = 1/2 ground state due to structural distortion. The insulator-to-metal transition in CaIrO3 will spur new researches to explore more exotic ground state, including superconductivity, in post-perovskite Mott insulators.

Alcohol-free alkoxide process for containing nuclear waste

DOEpatents

Pope, James M.; Lahoda, Edward J.

1984-01-01

Disclosed is a method of containing nuclear waste. A composition is first prepared of about 25 to about 80%, calculated as SiO.sub.2, of a partially hydrolyzed silicon compound, up to about 30%, calculated as metal oxide, of a partially hydrolyzed aluminum or calcium compound, about 5 to about 20%, calculated as metal oxide, of a partially hydrolyzed boron or calcium compound, about 3 to about 25%, calculated as metal oxide, of a partially hydrolyzed sodium, potassium or lithium compound, an alcohol in a weight ratio to hydrolyzed alkoxide of about 1.5 to about 3% and sufficient water to remove at least 99% of the alcohol as an azeotrope. The azeotrope is boiled off and up to about 40%, based on solids in the product, of the nuclear waste, is mixed into the composition. The mixture is evaporated to about 25 to about 45% solids and is melted and cooled.

Stable dimeric magnesium(I) compounds: from chemical landmarks to versatile reagents.

PubMed

Stasch, Andreas; Jones, Cameron

2011-06-07

The chemistry of the s-block metals is dominated by the +1 oxidation state for the Alkali metals (group 1) and the +2 oxidation state for the Alkaline Earth metals (group 2). In recent years, a series of stable dimeric magnesium(I) compounds has been prepared and their chemistry has started to develop. These complexes feature "deformable" Mg-Mg single bonds and are stabilised by sterically demanding and chelating anionic N-ligands that prevent their disproportionation. They have rapidly proven useful in organic and organometallic/inorganic reduction reactions as hydrocarbon soluble, stoichiometric, selective and safe reducing agents. The scope of this perspective focuses on stable molecular compounds of the general type LMgMgL and describes their synthesis, structures, theoretical and spectroscopic studies as well as their further chemistry. Also, comparisons are drawn with related complexes including magnesium(II) hydrides and dimeric zinc(I) compounds.

Exploring the Photovoltaic Properties of Metal Bipyridine Complexes (Metal = Fe, Zn, Cr, and Ru) by Density Functional Theory

NASA Astrophysics Data System (ADS)

Irfan, Ahmad; Abbas, Ghulam

2018-03-01

The synthesis and characterisation of mononuclear Fe complexes were carried out by using bipyridine (Compound 1) at ambient conditions. Additionally, three more derivatives were designed by substituting the central Fe metal with Zn, Cr, and Ru (Compound 2, Compound 3, and Compound 4), respectively. The ground state geometry calculations were carried out by using density functional theory (DFT) at B3LYP/6-31G** (LANL2DZ) level of theory. We shed light on the frontier molecular orbitals, electronic properties, photovoltaic parameters, and structure-property relationship. The open-circuit voltage is a promising parameter that considerably affects the photovoltaic performance; thus, we have estimated its value by considering the complexes as donors whereas TiO2 and/or Si were used as acceptors. The solar cell performance behaviour was also studied by shedding light on the band alignment and energy level offset.

Zinc phosphate conversion coatings

DOEpatents

Sugama, Toshifumi

1997-01-01

Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate .alpha.-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal.

Zinc phosphate conversion coatings

DOEpatents

Sugama, T.

1997-02-18

Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate {alpha}-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal. 33 figs.

Preparations and properties of anti-corrosion additives of water-soluble metal working fluids for aluminum alloy materials.

PubMed

Watanabe, Shoji

2008-01-01

This short review describes various types of anti-corrosion additives of water-soluble metal working fluids for aluminum alloy materials. It is concerned with synthetic additives classified according to their functional groups; silicone compounds, carboxylic acids and dibasic acids, esters, Diels-Alder adducts, various polymers, nitrogen compounds, phosphoric esters, phosphonic acids, and others. Testing methods for water-soluble metal working fluids for aluminum alloy materials are described for a practical application in a laboratory.

MOD silver metallization for photovoltaics

NASA Technical Reports Server (NTRS)

Vest, G. M.; Vest, R. W.

1985-01-01

The feasibility of utilizing metallo-organic decomposition (MOD) silver inks were investigated for front contact metallization of solar cells. Generic synthesis procedures were developed for all metallo-organic compounds investigated. Silver neodecanoate was found to be the most suitable silver metallo-organic compound for use in thick film inks, but the quality of the inks was found to be highly dependent on its purity. Although neither the process nor inks were completely optimized for solar cell front contact metallization, they show great promise for this application.

Magnetic susceptibilities of actinide 3d-metal intermetallic compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muniz, R.B.; d'Albuquerque e Castro, J.; Troper, A.

1988-04-15

We have numerically calculated the magnetic susceptibilities which appear in the Hartree--Fock instability criterion for actinide 3d transition-metal intermetallic compounds. This calculation is based on a previous tight-binding description of these actinide-based compounds (A. Troper and A. A. Gomes, Phys. Rev. B 34, 6487 (1986)). The parameters of the calculation, which starts from simple tight-binding d and f bands are (i) occupation numbers, (ii) ratio of d-f hybridization to d bandwidth, and (iii) electron-electron Coulomb-type interactions.

United States Air Force Summer Faculty Research Program 1989. Program Technical Report. Volume 1

DTIC Science & Technology

1989-12-01

Amy Miller Transition-Metal Compounds ; Reactions of Iron and Iron Carbonyl Anions 59 Acidities of Iron Hydride and Various Dr. Thomas Miller...Transition-Metal Compounds ; Reactions of Iron and Iron Carbonyl Anions (Same Report as Dr. Amy Miller) 60 C02(4.3pm) Vibrational Temperatures and Dr. Henry...Release. Table VIII gives data on the the two alloy systems, Pd/Al and Ni/Al. It also gives some properties of the compound , Pd/Hz. A brief description of

Controlling magnetism of a complex metallic system using atomic individualism.

PubMed

Mudryk, Y; Paudyal, D; Pecharsky, V K; Gschneidner, K A; Misra, S; Miller, G J

2010-08-06

When the complexity of a metallic compound reaches a certain level, a specific location in the structure may be critically responsible for a given fundamental property of a material while other locations may not play as much of a role in determining such a property. The first-principles theory has pinpointed a critical location in the framework of a complex intermetallic compound--Gd(5)Ge(4)--that resulted in a controlled alteration of the magnetism of this compound using precise chemical tools.

Highly selective catalytic process for synthesizing 1-hexene from ethylene

DOEpatents

Sen, Ayusman; Murtuza, Shahid; Harkins, Seth B.; Andes, Cecily

2002-01-01

Ethylene is trimerized to form 1-hexene, at a selectivity of up to about 99 mole percent, by contacting ethylene, at an ethylene pressure of from about 200-1500 psig and at a reaction temperature of from about 0.degree. C. to about 100.degree. C., with a catalyst comprising a tantalum compound (e.g., TaCl.sub.5) and a alkylating component comprising a metal hydrocarbyl compound or a metal hydrocarbyl halide compound (e.g., Sn(CH.sub.3).sub.4).

New Sulfide Compounds MeXMn1-XS (Me=3d Metal) with the Colossal Magnetoresistance Effect

DTIC Science & Technology

2006-05-19

is to synthesize the new MeXMn1-XS (Me=3d-metal) sulfide compounds and to study the electrical, magnetic and magnetoresistive properties . Recently...oxide compounds of manganese (LaMnO3-type) with perovskite structure have been intensively investigated. This interest is caused by the observation of... properties of the materials with different structure. It is known that alpha - MnS manganese monosulfide, similar to LaMnO3, has the specific

Covalent bonds against magnetism in transition metal compounds

PubMed Central

Streltsov, Sergey V.; Khomskii, Daniel I.

2016-01-01

Magnetism in transition metal compounds is usually considered starting from a description of isolated ions, as exact as possible, and treating their (exchange) interaction at a later stage. We show that this standard approach may break down in many cases, especially in 4d and 5d compounds. We argue that there is an important intersite effect—an orbital-selective formation of covalent metal–metal bonds that leads to an “exclusion” of corresponding electrons from the magnetic subsystem, and thus strongly affects magnetic properties of the system. This effect is especially prominent for noninteger electron number, when it results in suppression of the famous double exchange, the main mechanism of ferromagnetism in transition metal compounds. We study this mechanism analytically and numerically and show that it explains magnetic properties of not only several 4d–5d materials, including Nb2O2F3 and Ba5AlIr2O11, but can also be operative in 3d transition metal oxides, e.g., in CrO2 under pressure. We also discuss the role of spin–orbit coupling on the competition between covalency and magnetism. Our results demonstrate that strong intersite coupling may invalidate the standard single-site starting point for considering magnetism, and can lead to a qualitatively new behavior. PMID:27601669

Polymer-coated nanoparticles: Carrier platforms for hydrophobic water- and air-sensitive metallo-organic compounds.

PubMed

Valdeperez, Daniel; Wang, Tianqiang; Eußner, Jens P; Weinert, Bastian; Hao, Jianyuan; Parak, Wolfgang J; Dehnen, Stefanie; Pelaz, Beatriz

2017-03-01

Many of the relevant compounds for anticancer therapy are metal-based compounds (metallodrugs), being platinum-based drugs such as cisplatin, carboplatin (Paraplatin ® ), and oxaliplatin (Eloxatin ® ) the most widely used. Despite this, their application is limited by issues such as cell-acquired platinum resistance and manifold side effects following systemic delivery. Thus, the development of new metal-based compounds is highly needed. The catalytic properties of a variety of metal-based compounds are nowadays very well known, which opens new opportunities to take advantage of them inside living cells or organisms. However, many of these compounds are hydrophobic and thus not soluble in aqueous solution, as they lack stability against water or oxygen presence. Thus, versatile platforms capable of enhancing the features of these compounds in aqueous solutions are of importance in the development of new drugs. Surface engineered nanoparticles may render metallodrugs with good colloidal stability in water and in complex media containing high salt concentration and/or proteins. Herein, polymer coated nanoparticles are proposed as a platform to link insoluble and water/oxygen sensitive drugs. The linkage of insoluble and oxygen sensitive tin clusters to nanoparticles is presented, aiming to enhance both, the solubility and the stability of these compounds in water, which may be an alternative approach in the development of metal-based drugs. The formation of the cluster-nanoparticle system was confirmed via inductively coupled plasma mass spectrometry experiments. The catalytic activity and the stability of the cluster in water were studied through the reduction of methylene blue. Results demonstrate that in fact the tin clusters could be transferred into aqueous solution and retained their catalytic activity. Copyright © 2016 Elsevier Ltd. All rights reserved.

X-ray absorption spectroscopy systematics at the tungsten L-edge.

PubMed

Jayarathne, Upul; Chandrasekaran, Perumalreddy; Greene, Angelique F; Mague, Joel T; DeBeer, Serena; Lancaster, Kyle M; Sproules, Stephen; Donahue, James P

2014-08-18

A series of mononuclear six-coordinate tungsten compounds spanning formal oxidation states from 0 to +VI, largely in a ligand environment of inert chloride and/or phosphine, was interrogated by tungsten L-edge X-ray absorption spectroscopy. The L-edge spectra of this compound set, comprised of [W(0)(PMe3)6], [W(II)Cl2(PMePh2)4], [W(III)Cl2(dppe)2][PF6] (dppe = 1,2-bis(diphenylphosphino)ethane), [W(IV)Cl4(PMePh2)2], [W(V)(NPh)Cl3(PMe3)2], and [W(VI)Cl6], correlate with formal oxidation state and have usefulness as references for the interpretation of the L-edge spectra of tungsten compounds with redox-active ligands and ambiguous electronic structure descriptions. The utility of these spectra arises from the combined correlation of the estimated branching ratio of the L3,2-edges and the L1 rising-edge energy with metal Zeff, thereby permitting an assessment of effective metal oxidation state. An application of these reference spectra is illustrated by their use as backdrop for the L-edge X-ray absorption spectra of [W(IV)(mdt)2(CO)2] and [W(IV)(mdt)2(CN)2](2-) (mdt(2-) = 1,2-dimethylethene-1,2-dithiolate), which shows that both compounds are effectively W(IV) species even though the mdt ligands exist at different redox levels in the two compounds. Use of metal L-edge XAS to assess a compound of uncertain formulation requires: (1) Placement of that data within the context of spectra offered by unambiguous calibrant compounds, preferably with the same coordination number and similar metal ligand distances. Such spectra assist in defining upper and/or lower limits for metal Zeff in the species of interest. (2) Evaluation of that data in conjunction with information from other physical methods, especially ligand K-edge XAS. (3) Increased care in interpretation if strong π-acceptor ligands, particularly CO, or π-donor ligands are present. The electron-withdrawing/donating nature of these ligand types, combined with relatively short metal-ligand distances, exaggerate the difference between formal oxidation state and metal Zeff or, as in the case of [W(IV)(mdt)2(CO)2], exert the subtle effect of modulating the redox level of other ligands in the coordination sphere.

Tannin-Metal Interactions in Soils: An Incubation-Extraction Approach in Hill-Land Environments

NASA Astrophysics Data System (ADS)

Gonzalez, J. M.; Halvorson, J. J.

2007-12-01

Tannins, plant polyphenols known to react with proteins, metals and soil organic matter, are commonly found in the vegetation growing in Appalachian hill-lands. Establishing silvopastoral grazing systems in these environments is a means for improving productivity however the fate of tannins in soils and, in particular, the effect on solubility/mobility of metals in soils is poorly understood. Soils from forest and pasture systems were sampled from two depths, treated with tannic acid or related phenolic compounds, and analyzed for metals in solution. The amount of Mn and Ca detected in solution varied among the different phenolic treatments, highest for gallic acid, and was also influenced by depth and land use. As expected, the Ca content in solution was correlated with the electrical conductivity (EC) and the Mn content was correlated with the redox potential in solution. Interestingly, the EC was also correlated with both Mn content and redox potential. The higher Ca content found in solution may result from the low pH of the phenolic compounds. The higher Mn in solution may result from the redox reaction of Mn (IV) oxides with the phenolic compounds, producing soluble Mn2+ and quinones. These quinones are very reactive compounds that can self-polymerize and/or copolymerize with other biomolecules, such as amino-containing compounds and carbohydrates, to form humic-like substances. Successful management of silvopastures, requires an understanding of factors that affect the quality and quantity of plant secondary compounds like tannins entering soil not only to increase forage productivity but also to enhance formation/stabilization of soil organic matter to increase nutrient cycling and reduce the toxicity risk of some metals such as Mn.

Unraveling the multi-functional behavior in a series of Metal Organic Frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanda, Suresh; Biswas, Soumava; Parshamoni, Srinivasulu

2015-09-15

Three new 2D/3D Metal-Organic Frameworks (MOFs), ([Zn(2,6-ndc)(aldrithiol)]·3(H{sub 2}O)){sub n} (1), ([Co(2,6-ndc)(aldrithiol)(H{sub 2}O){sub 2}]·2(H{sub 2}O)){sub n} (2), ([Cd{sub 2}(2,6-ndc){sub 2}(aldrithiol){sub 2}(H{sub 2}O){sub 2}]·(aldrithiol)·(EtOH)·3(H{sub 2}O)){sub n} (3), (2,6-ndc = 2,6-naphthalene dicarboxylic acid; aldrithiol = 4,4'-dipyridyl disulphide) have been synthesized and structurally characterized. Compounds 1 and 2 have 2D layered architectures with similar framework topology whereas 3 is a 2-fold interwoven three dimensional framework. Sorption studies reveal that compounds 1-3 selectively adsorbs CO{sub 2} over other gases and H{sub 2}O over other solvents. Proton conductivity study of compounds 1 and 2 show highest values of 6.73 x 10{sup -7} S.cm{sup -1}, 1.96 xmore » 10{sup -5} S.cm{sup -1} at 318 K and 95% RH and these values are humidity dependent. Photoluminescent properties of compounds 1 and 3 show metal perturbed (π*–π and π*-n) intra ligand charge transfer transitions. Additionally, Compound 3 also displays reversible adsorption of molecular iodine. - Graphical abstarct: Three new 2D/3D interpenetrated MOFs are synthesized and their multifunctional material properties such as adsorption, proton conduction, iodine adsorption as well as luminscence have been explored. - Highlights: • We report multifunctional material properties in a series MOFs (Compounds 1-3) • All the compounds show selective adsorption of CO{sub 2} over other gases and H{sub 2}O over other solvents. • The proton conduction property studies of all the compounds reveal the humidity dependent conductivity. • Compound 2 shows reversible adsorption of molecular iodine in the framework. • Photoluminescent properties of compounds 1 and 2 show metal perturbed intra ligand charge transfer transitions.« less

Metal anesthesia circuit components stop the progression of laser fires.

PubMed

Sosis, M B; Braverman, B

1994-01-01

To determine whether metallic Y-pieces and elbows would halt the progression of a laser-induced endotracheal tube fire. A segment of polyvinyl chloride endotracheal tube was attached to either an all-plastic anesthesia circle breathing system (n = 5) or a circuit consisting of a metal Y-piece and elbow with plastic hoses (n = 5). In each case, an Nd-YAG laser was used to ignite the endotracheal tube segment and attached anesthesia circuit as 5 L/min of oxygen was flowing through them. Research laboratory of a university-affiliated metropolitan medical center. The flames from the endotracheal tubes burned through the 22 mm hoses that were part of the all-plastic circuits in 49.5 +/- 8.8 seconds (mean +/- SD). In none of the trials with the metal components did the fire advance beyond the endotracheal tube's 15 mm adapter. Metal circuit components halt the progression of laser-induced endotracheal tube fires toward the anesthesia machine.

Selected trace metals and organic compounds and bioavailability of selected organic compounds in soils, Hackberry Flat, Tillman County, Oklahoma, 1994-95

USGS Publications Warehouse

Becker, M.F.

1997-01-01

In 1995 the Oklahoma Department of Wildlife Conservation acquired a drained wetland in southwest Oklahoma known as Hackberry Flat. Following restoration by Wildlife Conservation the wetland will be used by migratory birds and waterfowl. If naturally occurring trace metals and residual organic compounds from agriculture and industry were present, they may have posed a potential biohazard and were a concern for Wildlife Conservation. The U. S. Geological Survey, in cooperation with Wildlife Conservation and the Oklahoma Geological Survey, examined the soils of Hackberry Flat to determine trace metal concentrations, presence of selected organic compounds, and the bioavailability of selected organic compounds in the soils. The purpose of this report is to present the data that establish the baseline concentrations of selected trace metals and organic compounds in the soils of Hackberry Flat prior to wetland restoration. Sampling and analysis were performed using two approaches. One was to collect soil samples and analyze the composition with standard laboratory practices. The second exposed composite soils samples to organic-free water and a semipermeable membrane device that mimics an organism and then analyzed the device. Ten soil samples were collected in 1994 to be analyzed for trace metals, organochlorine pesticides, and polychlorinated biphenyls. Soil samples tested for bioavailability of selected organic compounds were collected in 1995. Most of the 182 soil samples collected were from the center of every 40-acre quarter-quarter section owned by the Wildlife Conservation. The samples were grouped by geographical area with a maximum of 16 sample sites per group. Concentrations of most selected trace metals measured from soils in Hackberry Flat are within the range of mean concentrations measured in cultivated soils within the United States. Organochlorine pesticides, polychlorinated biphenyls, and polyaromatic hydrocarbons were not found at concentrations above the analytical detection levels and, if present, in the soil samples are at concentrations below the detection level of the analytical method used. Organochlorine pesticides, total polychlorinated biphenyls, and polyaromatic hydrocarbons were not detected in any of the semipermeable membrane devices at the analytical detection levels.

Antioxidant response of Phragmites australis to Cu and Cd contamination.

PubMed

Rocha, A Cristina S; Almeida, C Marisa R; Basto, M Clara P; Vasconcelos, M Teresa S D

2014-11-01

Metals are known to induce oxidative stress in plant cells. Antioxidant thiolic compounds are known to play an important role in plants׳ defence mechanisms against metal toxicity but, regarding salt marsh plants, their role is still very poorly understood. In this work, the involvement of non-protein thiols (NPT), such as cysteine (Cys), reduced glutathione (GSH), oxidised glutathione (GSSG) and total acid-soluble SH compounds (total thiols), in the tolerance mechanisms of the marsh plant Phragmites australis against Cu and Cd toxicity was assessed. Specimens of this plant, freshly harvested in an estuarine salt marsh, were exposed, for 7 days, to rhizosediment soaked with the respective elutriate contaminated with Cu (0, 10 and 100 mg/L) or Cd (0, 1, 10 mg/L). In terms of NPT production, Cu and Cd contamination induced different responses in P. australis. The content of Cys increased in plant tissue after plant exposure to Cu, whereas Cd contamination led to a decrease in GSSG levels. In general, metal contamination did not cause a significant variation on GSH levels. Both metals influenced, to some extent, the production of other thiolic compounds. Despite the accumulation of considerable amounts of Cu and Cd in belowground tissues, no visible toxicity signs were observed. So, antioxidant thiolic compounds were probably involved in the mechanisms used by P. australis to alleviate metal toxicity. As P. australis is considered suitable for phytostabilising metal-contaminated sediments, understanding its tolerance mechanisms to toxic metals is important to optimise the conditions for applying this plant in phytoremediation procedures. Copyright © 2014 Elsevier Inc. All rights reserved.

Tuning the formations of metal-1,3,5-benzenetricarboxylate frameworks via the assistance of amino acids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lei, Xiao-Ping; Lian, Ting-Ting; Chen, Shu-Mei, E-mail: csm@fzu.edu.cn

Seven new metal-1,3,5-benzenetricarboxylate coordination polymers have been synthesized by modification of auxiliary components during the assembly reactions. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by XRD and TGA. Interestingly, they show fascinating topological structures. Compounds 1 and 2 possess the undulating layer structure with 3-connected hcb network and (3,6)-connected kgd network. Compound 3 possesses three-dimensional (3D) pillared-layer structure with 3-connected 2-fold interpenetrating srs net. Compound 4 also has the 3D 2-fold interpenetrating pillared-layer structure; however, it has (3,5)-connected hms topology because the Cd(II) center is 5-connected. Compound 5 possess 3D structure through hydrogen bondingmore » interactions between ladder-like layers. Compounds 6 and 7 have the similar 3D frameworks with 4-connected umc net and (3,7)-connected (3.4.5)(3{sup 2}.4{sup 6}.5{sup 5}.6{sup 8}) topology, respectively. The photoluminescent properties of compounds 2–7 were also investigated. - Graphical abstract: Presented here are seven new metal-1,3,5-benzenetricarboxylate coordination polymers with diverse structures from 2D layers to 3D open frameworks. The synthesis and structural diversity of these compounds are determined by the additional amino acids as unusual buffering agents. - Highlights: • Structural diversity of metal-1,3,5-benzenetricarboxylate frameworks. • Tuning structural topologies of MOFs via the assistance of amino acids. • Amino acids as unusual buffering agents for the synthesis of MOFs.« less

Use of response surface methodology to evaluate the effect of metal ions (Ca2+, Ni2+, Mn2+, Cu2+) on production of antifungal compounds by Paenibacillus polymyxa.

PubMed

Raza, Waseem; Hongsheng, Wu; Qirong, Shen

2010-03-01

The effects of four metal ions (Ca(2+), Ni(2+), Mn(2+) and Cu(2+)) were evaluated on growth and production of antifungal compounds by Paenibacillus polymyxa SQR-21 and a quadratic predictive model was developed using response surface methodology (RSM). The results revealed, Mn(2+) and Ni(2+) showed most positive synergistic interactive affect on production of antifungal compounds followed by the positive interactive synergistic affect of Cu(2+) and Ni(2+) and then Mn(2+) and Cu(2+). While the interactive effect of Ca(2+) with all other three metals inhibited the production of antifungal compounds. The Mn(2+) (P=0.0384), Ni(2+) (P=0.0004) and Cu(2+) (P=0.0117) significantly affected the production of antifungal compounds while the effect of Ca(2+) (P=0.1851) was less significant. The maximum growth (OD(600)=1.55) was obtained at 500 (0), 125 (0), 100 (-2) and 37.5 (0) microM levels and the maximum size of inhibition zone (31 mm) was measured at 400 (-1), 150 (1), 400 (1) and 25 microM (-1) levels of Ca(2+), Mn(2+), Ni(2+) and Cu(2+), respectively. The RSM model provided an easy and effective way to determine the interactive effect of metal ions on production of antifungal compounds by P. polymyxa SQR-21 so that optimum media recipes can be developed to produce maximum amounts of antifungal compounds under laboratory and commercial fermentation conditions. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Emerging ferroelectric transistors with nanoscale channel materials: the possibilities, the limitations

NASA Astrophysics Data System (ADS)

Hong, Xia

2016-03-01

Combining the nonvolatile, locally switchable polarization field of a ferroelectric thin film with a nanoscale electronic material in a field effect transistor structure offers the opportunity to examine and control a rich variety of mesoscopic phenomena and interface coupling. It is also possible to introduce new phases and functionalities into these hybrid systems through rational design. This paper reviews two rapidly progressing branches in the field of ferroelectric transistors, which employ two distinct classes of nanoscale electronic materials as the conducting channel, the two-dimensional (2D) electron gas graphene and the strongly correlated transition metal oxide thin films. The topics covered include the basic device physics, novel phenomena emerging in the hybrid systems, critical mechanisms that control the magnitude and stability of the field effect modulation and the mobility of the channel material, potential device applications, and the performance limitations of these devices due to the complex interface interactions and challenges in achieving controlled materials properties. Possible future directions for this field are also outlined, including local ferroelectric gate control via nanoscale domain patterning and incorporating other emergent materials in this device concept, such as the simple binary ferroelectrics, layered 2D transition metal dichalcogenides, and the 4d and 5d heavy metal compounds with strong spin-orbit coupling.

Low-Temperature Synthesis of New Ternary Chalcogenide Compounds of Copper, Gold, and Mercury Using Alkali Metal Polychalcogenide Fluxes

NASA Astrophysics Data System (ADS)

Park, Younbong

In last two decades great efforts have been exerted to find new materials with interesting optical, electrical, and catalytic properties. Metal chalcogenides have been studied extensively because of their interesting physical properties and rich structural chemistry, among the potential materials. Prior to this work, most known metal chalcogenides had been synthesized at high temperature (T > 500^circC). Intermediate temperature synthesis in solid state chemistry was seldom pursued because of the extremely slow diffusion rates between reactants. This intermediate temperature regime could be a new synthesis condition if one looks for new materials with unusual structural features and properties. Metastable or kinetically stable compounds can be stabilized in this intermediate temperature regime, in contrast to the thermodynamically stable high temperature compounds. Molten salts, especially alkali metal polychalcogenide fluxes, can provide a route for exploring new chalcogenide materials at intermediate temperatures. These fluxes are very reactive and melt as low as 145^circC (mp of K_2S_4). Using these fluxes as reaction media, we have encountered many novel chalcogenide compounds with unusual structures and interesting electrical properties (semiconductors to metallic conductors). Low-dimensional polychalcogenide compounds of alpha-ACuQ_4 (A = K, Cs; Q = S, Se), beta -KCuS_4, KAuQ_5 (Q = S, Se), K_3AuSe_ {13}, Na_3AuSe _8, and CsAuSe_3 exhibit the beautiful structural diversity and bonding flexibility of the polychalcogenide ligands. In addition, many novel chalcogenide compounds of Cu, Hg, and Au with low-dimensional structures. The preparation of novel mixed -valence Cu compounds, K_2Cu _5Te_5, Cs _3Cu_8Te_ {10}, Na_3Cu _4Se_4, K _3Cu_8S_4 Te_2, and KCu_4 S_2Te, which show interesting metallic properties, especially underscores the enormous potential of the molten salt method for the synthesis of new chalcogenide materials with interesting physical properties. The materials prepared in this study can be classified as a new class of chalcogenide compounds due to their unique structures. In this dissertation the synthesis, characterization with emphasis on structures, charge transport properties, and magnetic susceptibilities of the materials will be illustrated.

Method for producing nanocrystalline multicomponent and multiphase materials

DOEpatents

Eastman, Jeffrey A.; Rittner, Mindy N.; Youngdahl, Carl J.; Weertman, Julia R.

1998-01-01

A process for producing multi-component and multiphase nanophase materials is provided wherein a plurality of elements are vaporized in a controlled atmosphere, so as to facilitate thorough mixing, and then condensing and consolidating the elements. The invention also provides for a multicomponent and multiphase nanocrystalline material of specified elemental and phase composition having component grain sizes of between approximately 1 nm and 100 nm. This material is a single element in combination with a binary compound. In more specific embodiments, the single element in this material can be a transition metal element, a non-transition metal element, a semiconductor, or a semi-metal, and the binary compound in this material can be an intermetallic, an oxide, a nitride, a hydride, a chloride, or other compound.

Synthesis of phthalide-fused indoline by microwave irradiation and preliminary binding study with metal cations

NASA Astrophysics Data System (ADS)

Ling, Sheryn Wong Shue; Latip, Jalifah; Hassan, Nurul Izzaty; Hasbullah, Siti Aishah

2018-04-01

An efficient and green method of synthesizing phthalide-fused indoline, 3-[(1,3,3-trimethylindolin-2-ylidene)methyl]isobenzofuran-1(3H)-one (3) has been developed by the coupling reaction of 1,3,3-trimethyl-2-methyleneindoline, 1 and phthalaldehydic acid, 2 under solvent-free domestic microwave irradiation. The compound was produced with an excellent yield (98 %) and at a shorter reaction time (5 min) as compared to the conventional method. Compound 3 was fully characterized by analytical and spectral methods. Preliminary binding study of 3 towards different types of metal cations was done by "naked eye" colorimetric detection and UV-vis spectrophotometer. Compound 3 exhibits good selectivity and sensitivity for Sn2+ compared to other metal cations.

Low work function, stable thin films

DOEpatents

Dinh, Long N.; McLean, II, William; Balooch, Mehdi; Fehring, Jr., Edward J.; Schildbach, Marcus A.

2000-01-01

Generation of low work function, stable compound thin films by laser ablation. Compound thin films with low work function can be synthesized by simultaneously laser ablating silicon, for example, and thermal evaporating an alkali metal into an oxygen environment. For example, the compound thin film may be composed of Si/Cs/O. The work functions of the thin films can be varied by changing the silicon/alkali metal/oxygen ratio. Low work functions of the compound thin films deposited on silicon substrates were confirmed by ultraviolet photoelectron spectroscopy (UPS). The compound thin films are stable up to 500.degree. C. as measured by x-ray photoelectron spectroscopy (XPS). Tests have established that for certain chemical compositions and annealing temperatures of the compound thin films, negative electron affinity (NEA) was detected. The low work function, stable compound thin films can be utilized in solar cells, field emission flat panel displays, electron guns, and cold cathode electron guns.

Alkanes from Bioderived Furans by using Metal Triflates and Palladium-Catalyzed Hydrodeoxygenation of Cyclic Ethers.

PubMed

Song, Hai-Jie; Deng, Jin; Cui, Min-Shu; Li, Xing-Long; Liu, Xin-Xin; Zhu, Rui; Wu, Wei-Peng; Fu, Yao

2015-12-21

Using a metal triflate and Pd/C as catalysts, alkanes were prepared from bioderived furans in a one-pot hydrodeoxygenation (HDO) process. During the reaction, the metal triflate plays a crucial role in the ring-opening HDO of furan compounds. The entire reaction process has goes through two major phases: at low temperatures, saturation of the exocyclic double bond and furan ring are catalyzed by Pd/C; at high temperatures, the HDO of saturated furan compounds is catalyzed by the metal triflate. The reaction mechanism was verified by analyzing the changes of the intermediates during the reaction. In addition, different metal triflates, solvents, and catalyst recycling were also investigated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Defect-mediated, thermally-activated encapsulation of metals at the surface of graphite

DOE PAGES

Zhou, Yinghui; Lii-Rosales, Ann; Kim, Minsung; ...

2017-11-04

Here, we show that 3 metals – Dy, Ru, and Cu – can form multilayer intercalated (encapsulated) islands at the graphite (0001) surface if 2 specific conditions are met: Defects are introduced on the graphite terraces to act as entry portals, and the metal deposition temperature is well above ambient. Focusing on Dy as a prototype, we show that surface encapsulation is much different than bulk intercalation, because the encapsulated metal takes the form of bulk-like rafts of multilayer Dy, rather than the dilute, single-layer structure known for the bulk compound. Carbon-covered metallic rafts even form for relatively unreactive metalsmore » (Ru and Cu) which have no known bulk intercalation compound.« less

Intermetallic M--Sn.sub.5 (M=Fe, Cu, Co, Ni) compound and a method of synthesis thereof

DOEpatents

Wang, Xiao-Liang; Han, Weiqiang

2017-09-05

Novel intermetallic materials are provided that are composed of tin and one or more additional metal(s) having a formula M.sub.(1-x)-Sn.sub.5, where -0.1.ltoreq.x.ltoreq.0.5, with 0.01.ltoreq.x.ltoreq.0.4 being more preferred and the second metallic element (M) is selected from iron (Fe), copper (Cu), cobalt (Co), nickel (Ni), and a combination of two or more of those metals. Due to low concentration of the second metallic element, the intermetallic compound affords an enhanced capacity applicable for electrochemical cells and may serve as an intermediate phase between Sn and MSn.sub.2. A method of synthesizing these intermetallic materials is also disclosed.

Nonconsumable electrode assembly and use thereof for the electrolytic production of metals and silicon

DOEpatents

Byrne, Stephen C.; Ray, Siba P.

1984-01-01

A nonconsumable electrode assembly suitable for use in the production of metal by electrolytic reduction of a metal compound dissolved in a molten salt, the assembly comprising a metal conductor attached to a ceramic electrode body by a metal bond on a portion of the body having a level of free metal or metal alloy sufficient to effect a metal bond.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Yinghui; Lii-Rosales, Ann; Kim, Minsung

Here, we show that 3 metals – Dy, Ru, and Cu – can form multilayer intercalated (encapsulated) islands at the graphite (0001) surface if 2 specific conditions are met: Defects are introduced on the graphite terraces to act as entry portals, and the metal deposition temperature is well above ambient. Focusing on Dy as a prototype, we show that surface encapsulation is much different than bulk intercalation, because the encapsulated metal takes the form of bulk-like rafts of multilayer Dy, rather than the dilute, single-layer structure known for the bulk compound. Carbon-covered metallic rafts even form for relatively unreactive metalsmore » (Ru and Cu) which have no known bulk intercalation compound.« less

Membrane extraction with thermodynamically unstable diphosphonic acid derivatives

DOEpatents

Horwitz, Earl Philip; Gatrone, Ralph Carl; Nash, Kenneth LaVerne

1997-01-01

Thermodynamically-unstable complexing agents which are diphosphonic acids and diphosphonic acid derivatives (or sulphur containing analogs), like carboxyhydroxymethanediphosphonic acid and vinylidene-1,1-diphosphonic acid, are capable of complexing with metal ions, and especially metal ions in the II, III, IV, V and VI oxidation states, to form stable, water-soluble metal ion complexes in moderately alkaline to highly-acidic media. However, the complexing agents can be decomposed, under mild conditions, into non-organic compounds which, for many purposes are environmentally-nondamaging compounds thereby degrading the complex and releasing the metal ion for disposal or recovery. Uses for such complexing agents as well as methods for their manufacture are also described.

Conditions affecting the formation of chlorinated carbon compounds during carbochlorination

NASA Astrophysics Data System (ADS)

Landsberg, A.; Wilson, R. D.; Burns, W.

1988-06-01

The Bureau of Mines, United States Department of the Interior, has conducted an extensive study of the relationship between various metal oxide carbochlorination reactions and carbon compound byproducts. Experiments in which oxides of titanium, zirconium, and aluminum with graphite, charcoal, metallurgical coke, and pctroleum coke were chlorinated at 600° to 1000 °C produced 136 identified and quantified carbon byproduct compounds. The 20 most abundant of these compounds were correlated with reactants and reaction conditions. Experimental results support a proposed carbochlorination reaction with an initial chlorine-carbon step followed by a reaction between the resulting chlorine-carbon products and the metal oxide.

ARPES investigations of parent compounds of 122 Fe-based superconductors and their 3d transition metal cousins

NASA Astrophysics Data System (ADS)

Richard, Pierre; Zhang, W.-L.; Wu, S.-F.; van Roekeghem, A.; Zhang, P.; Miao, H.; Qian, T.; Nie, S.-M.; Chen, G.-F.; Ding, H.; Xu, N.; Biermann, S.; Capan, C.; Fisk, Z.; Saparov, B. I.; Sefat, A. S.

2015-03-01

It is widely believed that the key ingredients for high-temperature superconductivity are already present in the non-superconducting parent compounds. With its ability to probe the single-particle electronic structure directly in the momentum space, ARPES is a very powerful tool to determine which parameters of the electronic structure are possibly relevant for promoting superconductivity. Here we report ARPES studies on the parent compounds of the 122 family of Fe-based superconductors and their 3 d transition metal pnictide cousins. In particular, we show that the Fe-compound exhibits the largest electronic correlations, possibly a determining factor for unconventional superconductivity.

Can thiol compounds be used as biomarkers of aquatic ecosystem contamination by cadmium?

PubMed Central

Kovářová, Jana; Svobodová, Zdeňka

2009-01-01

Due to anthropogenic activities, heavy metals still represent a threat for various trophic levels. If aquatic animals are exposed to heavy metals we can obviously observe considerable toxicity. It is well known that an organism affected by cadmium (Cd) synthesize low molecular mass thiol compounds rich in cysteine (Cys), such as metallothioneins (MT) and glutathione (GSH/GSSG). The aim of this study was to summarize the effect of Cd on level of thiol compounds in aquatic organisms, and evaluate that the concentrations of thiol compounds are effective indicators of Cd water pollution and explain their potential use in biomonitoring applications. PMID:21217850

Diffusion welded nonconsumable electrode assembly and use thereof for electrolytic production of metals and silicon

DOEpatents

Byrne, Stephen C.; Vasudevan, Asuri K.

1984-01-01

A nonconsumable electrode assembly suitable for use in the production of metal by electrolytic reduction of a metal compound dissolved in a molten salt, the assembly comprising a metal conductor diffusion welded to a portion of a ceramic electrode body having a level of free metal or metal alloy sufficient to effect a metal bond.

Sulfur and selenium antioxidants: challenging radical scavenging mechanisms and developing structure-activity relationships based on metal binding.

PubMed

Zimmerman, Matthew T; Bayse, Craig A; Ramoutar, Ria R; Brumaghim, Julia L

2015-04-01

Because sulfur and selenium antioxidants can prevent oxidative damage, numerous animal and clinical trials have investigated the ability of these compounds to prevent the oxidative stress that is an underlying cause of cardiovascular disease, Alzheimer's disease, and cancer, among others. One of the most common sources of oxidative damage is metal-generated hydroxyl radical; however, very little research has focused on determining the metal-binding abilities and structural attributes that affect oxidative damage prevention by sulfur and selenium compounds. In this review, we describe our ongoing investigations into sulfur and selenium antioxidant prevention of iron- and copper-mediated oxidative DNA damage. We determined that many sulfur and selenium compounds inhibit Cu(I)-mediated DNA damage and that DNA damage prevention varies dramatically when Fe(II) is used in place of Cu(I) to generate hydroxyl radical. Oxidation potentials of the sulfur or selenium compounds do not correlate with their ability to prevent DNA damage, highlighting the importance of metal coordination rather than reactive oxygen species scavenging as an antioxidant mechanism. Additional gel electrophoresis, mass spectrometry, and UV-visible studies confirmed sulfur and selenium antioxidant binding to Cu(I) and Fe(II). Ultimately, our studies established that both the hydroxyl-radical-generating metal ion and the chemical environment of the sulfur or selenium significantly affect DNA damage prevention and that metal coordination is an essential mechanism for these antioxidants. Copyright © 2015 Elsevier Inc. All rights reserved.

Understanding the Effect of Cation Disorder on the Voltage Profile of Lithium Transition-Metal Oxides

DOE PAGES

Abdellahi, Aziz; Urban, Alexander; Dacek, Stephen; ...

2016-07-13

Cation disorder is a phenomenon that is becoming increasingly important for the design of high-energy lithium transition metal oxide cathodes (LiMO 2) for Li-ion batteries. Disordered Li-excess rocksalts have recently been shown to achieve high reversible capacity, while in operando cation disorder has been observed in a large class of ordered compounds. The voltage slope (dV/dx u )is a critical quantity for the design of cation-disordered rocksalts, as it controls the Li capacity accessible at voltages below the stability limit of the electrolyte (~4.5-4.7 V). In this study, we develop a lattice model based on first principles to understand andmore » quantify the voltage slope of cation-disordered LiMO 2. We show that cation disorder increases the voltage slope of Li transition metal oxides by creating a statistical distribution of transition metal environments around Li sites, as well as by allowing Li occupation of highvoltage tetrahedral sites. We further demonstrate that the voltage slope increase upon disorder is generally smaller for highvoltage transition metals than for low-voltage transition metals due to a more effective screening of Li-M interactions by oxygen electrons. Short-range order in practical disordered compounds is found to further mitigate the voltage slope increase upon disorder. In conclusion, our analysis shows that the additional high-voltage tetrahedral capacity induced by disorder is smaller in Liexcess compounds than in stoichiometric LiMO 2 compounds.« less

Novel synthesis and applications of Thiomer solidification for heavy metals immobilization in hazardous ASR/ISW thermal residue.

PubMed

Baek, Jin Woong; Mallampati, Srinivasa Reddy; Park, Hung Suck

2016-03-01

The present paper reports the novel synthesis and application of Thiomer solidification for heavy metal immobilization in hazardous automobile shredder residues and industrial solid waste (ASR/ISW) thermal residues. The word Thiomer is a combination of the prefix of a sulfur-containing compound "Thio" and the suffix of "Polymer" meaning a large molecule compound of many repeated subunits. To immobilize heavy metals, either ASR/ISW thermal residues (including bottom and fly ash) was mixed well with Thiomer and heated at 140°C. After Thiomer solidification, approximately 91-100% heavy metal immobilization was achieved. The morphology and mineral phases of the Thiomer-solidified ASR/ISW thermal residue were characterized by field emission-scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction (XRD), which indicated that the amounts of heavy metals detectable on the ASR/ISW thermal residue surface decreased and the sulfur mass percent increased. XRD indicated that the main fraction of the enclosed/bound materials on the ASR/ISW residue contained sulfur associated crystalline complexes. The Thiomer solidified process could convert the heavy metal compounds into highly insoluble metal sulfides and simultaneously encapsulate the ASR/ISW thermal residue. These results show that the proposed method can be applied to the immobilization of ASR/ISW hazardous ash involving heavy metals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Environmental application of nanotechnology: air, soil, and water.

PubMed

Ibrahim, Rusul Khaleel; Hayyan, Maan; AlSaadi, Mohammed Abdulhakim; Hayyan, Adeeb; Ibrahim, Shaliza

2016-07-01

Global deterioration of water, soil, and atmosphere by the release of toxic chemicals from the ongoing anthropogenic activities is becoming a serious problem throughout the world. This poses numerous issues relevant to ecosystem and human health that intensify the application challenges of conventional treatment technologies. Therefore, this review sheds the light on the recent progresses in nanotechnology and its vital role to encompass the imperative demand to monitor and treat the emerging hazardous wastes with lower cost, less energy, as well as higher efficiency. Essentially, the key aspects of this account are to briefly outline the advantages of nanotechnology over conventional treatment technologies and to relevantly highlight the treatment applications of some nanomaterials (e.g., carbon-based nanoparticles, antibacterial nanoparticles, and metal oxide nanoparticles) in the following environments: (1) air (treatment of greenhouse gases, volatile organic compounds, and bioaerosols via adsorption, photocatalytic degradation, thermal decomposition, and air filtration processes), (2) soil (application of nanomaterials as amendment agents for phytoremediation processes and utilization of stabilizers to enhance their performance), and (3) water (removal of organic pollutants, heavy metals, pathogens through adsorption, membrane processes, photocatalysis, and disinfection processes).

Reactivity-based drug discovery using vitamin B(6)-derived pharmacophores.

PubMed

Wondrak, Georg T

2008-05-01

Endogenous reactive intermediates including photoexcited states of tissue chromophores, reactive oxygen species (ROS), reactive carbonyl species (RCS), transition metal ions, and Schiff bases have been implicated in the initiation and progression of diverse human pathologies including tumorigenesis, atherosclerosis, diabetes, and neurodegenerative disease. In contrast to structure-based approaches that target macromolecules by selective ligands, reactivity-based drug discovery uses chemical reagents as therapeutics that target reactive chemical species involved in human pathology. Reactivity-based design of prototype agents that effectively antagonize, modulate, and potentially even reverse the chemistry underlying tissue damage from oxidative and carbonyl stress therefore holds great promise in delivering significant therapeutic benefit. Apart from its established role as an essential cofactor for numerous enzymes, a large body of evidence suggests that B(6)-vitamers contain reactive pharmacophores that mediate therapeutically useful non-vitamin drug actions as potent antioxidants, metal chelators, carbonyl scavengers, Schiff base forming agents, and photosensitizers. Based on the fascinating chemical versatility of B(6)-derived pharmacophores, B(6)-vitamers are therefore promising lead compounds for reactivity-based drug design.

Unfolding the physics of URu 2Si 2 through silicon to phosphorus substitution

DOE PAGES

Gallagher, A.; Chen, K. -W.; Moir, C. M.; ...

2016-02-19

The heavy fermion intermetallic compound URu 2Si 2 exhibits a hidden-order phase below the temperature of 17.5 K, which supports both anomalous metallic behavior and unconventional superconductivity. While these individual phenomena have been investigated in detail, it remains unclear how they are related to each other and to what extent uranium f-electron valence fluctuations influence each one. Here we use ligand site substituted URu 2Si 2-xP x to establish their evolution under electronic tuning. We find that while hidden order is monotonically suppressed and destroyed for x ≤ 0.035, the superconducting strength evolves non-monotonically with a maximum near x ≈more » 0.01 and that superconductivity is destroyed near x ≈ 0.028. This behavior reveals that hidden order depends strongly on tuning outside of the U f-electron shells. Furthermore, it also suggests that while hidden order provides an environment for superconductivity and anomalous metallic behavior, it’s fluctuations may not be solely responsible for their progression.« less

Study of Corrosion Resistance Improvement by Metallic Coating for Overhead Transmission Line Conductor

NASA Astrophysics Data System (ADS)

Isozaki, Masanori; Adachi, Kouichi; Hita, Takanori; Asano, Yuji

Applying anti-corrosion grease and aluminum clad steel (AC) wires to ACSR has adopted as general methods to prevent overhead transmission line conductors and/or wires from corrosion. However, there are some cases that ineffectiveness of those means are reported on some transmission lines passing through acid atmosphere in the vicinity of a factory exhausting acid smoke. The feature of the corrosion caused by acid atmosphere is to show a higher speed in its progressing as well known. As means against such acid corrosion, application of high purity aluminum, selective removal of inter-metallic compound in aluminum and plastic coating wires has been reported before, and each has both of advantage and disadvantage actually. In the former letter, we reported the new type of anti-corrosion grease that shows an excellent property against acid atmosphere as well as in a salty circumstance. Here presents a new type of anti-corrosion technology of applying high corrosion resistance aluminum alloy or zinc coatings on each component wires of a conductor that we succeed in developing through a serial study of anti-corrosion methods on overhead transmission lines.

Experimental Observation of Redox-Induced Fe-N Switching Behavior as a Determinant Role for Oxygen Reduction Activity.

PubMed

Jia, Qingying; Ramaswamy, Nagappan; Hafiz, Hasnain; Tylus, Urszula; Strickland, Kara; Wu, Gang; Barbiellini, Bernardo; Bansil, Arun; Holby, Edward F; Zelenay, Piotr; Mukerjee, Sanjeev

2015-12-22

The commercialization of electrochemical energy conversion and storage devices relies largely upon the development of highly active catalysts based on abundant and inexpensive materials. Despite recent achievements in this respect, further progress is hindered by the poor understanding of the nature of active sites and reaction mechanisms. Herein, by characterizing representative iron-based catalysts under reactive conditions, we identify three Fe-N4-like catalytic centers with distinctly different Fe-N switching behaviors (Fe moving toward or away from the N4-plane) during the oxygen reduction reaction (ORR), and show that their ORR activities are essentially governed by the dynamic structure associated with the Fe(2+/3+) redox transition, rather than the static structure of the bare sites. Our findings reveal the structural origin of the enhanced catalytic activity of pyrolyzed Fe-based catalysts compared to nonpyrolyzed Fe-macrocycle compounds. More generally, the fundamental insights into the dynamic nature of transition-metal compounds during electron-transfer reactions will potentially guide rational design of these materials for broad applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manser, Joseph S.; Christians, Jeffrey A.; Kamat, Prashant V.

Here, a new chapter in the long and distinguished history of perovskites is being written with the breakthrough success of metal halide perovskites (MHPs) as solution-processed photovoltaic (PV) absorbers. The current surge in MHP research has largely arisen out of their rapid progress in PV devices; however, these materials are potentially suitable for a diverse array of optoelectronic applications. Like oxide perovskites, MHPs have ABX 3 stoichiometry, where A and B are cations and X is a halide anion. Here, the underlying physical and photophysical properties of inorganic (A = inorganic) and hybrid organic-inorganic (A = organic) MHPs are reviewedmore » with an eye toward their potential application in emerging optoelectronic technologies. Significant attention is given to the prototypical compound methylammonium lead iodide (CH 3NH 3PbI 3) due to the preponderance of experimental and theoretical studies surrounding this material. We also discuss other salient MHP systems, including 2- dimensional compounds, where relevant. More specifically, this review is a critical account of the interrelation between MHP electronic structure, absorption, emission, carrier dynamics and transport, and other relevant photophysical processes that have propelled these materials to the forefront of modern optoelectronics research.« less

Cross-linking proteins with bimetallic tetracarboxylate compounds of transition metals

DOEpatents

Kostic, Nenad M.; Chen, Jian

1991-03-05

Stable cross-linked complexes of transition-metal tetracarboxylates and proteins are formed. The preferred transition-metal is rhodium. The protein may be collagen or an enzyme such as a proteolytic enzyme.

Framework for metals risk assessment [ Journal Article

EPA Science Inventory

This is a science-based document that describes basic principles that address the special attributes and behaviors of metals and metal compounds to be considered when assessing their human health and ecological risks.

40 CFR 442.2 - General definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., organic chemicals including: alcohols, aldehydes, formaldehydes, phenols, peroxides, organic salts, amines, amides, other nitrogen compounds, other aromatic compounds, aliphatic organic chemicals, glycols, glycerines, and organic polymers; refractory organic compounds including: ketones, nitriles, organo-metallic...

Exploring monovalent copper compounds with oxygen and hydrogen

PubMed Central

Korzhavyi, Pavel A.; Soroka, Inna L.; Isaev, Eyvaz I.; Lilja, Christina; Johansson, Börje

2012-01-01

New important applications of copper metal, e.g., in the areas of hydrogen production, fuel cell operation, and spent nuclear fuel disposal, require accurate knowledge of the physical and chemical properties of stable and metastable copper compounds. Among the copper(I) compounds with oxygen and hydrogen, cuprous oxide Cu2O is the only one stable and the best studied. Other such compounds are less known (CuH) or totally unknown (CuOH) due to their instability relative to the oxide. Here we combine quantum-mechanical calculations with experimental studies to search for possible compounds of monovalent copper. Cuprous hydride (CuH) and cuprous hydroxide (CuOH) are proved to exist in solid form. We establish the chemical and physical properties of these compounds, thereby filling the existing gaps in our understanding of hydrogen- and oxygen-related phenomena in Cu metal. PMID:22219370

Formation, characterization, aggregation, fluorescence and antioxidant properties of novel tetrasubstituted metal-free and metallophthalocyanines bearing (4-(methylthio)phenoxy) moieties

NASA Astrophysics Data System (ADS)

Yıldırım, Nurdan; Bilgiçli, Ahmet T.; Alici, Esma Hande; Arabacı, Gulnur; Yarasir, M. Nilüfer

2017-09-01

The synthesis and characterization of peripherally tetra 4-(methylthio)phenoxy substituted metal-free(2), Zn(II) (3) and Co(II) (4) phthalocyanine derivatives were reported. These newly synthesized phthalocyanine derivatives showed the enhanced solubility in organic solvents and they were characterized by a combination of elemental analysis, FTIR, 1H NMR, 13C NMR, UV-vis and MALDI-TOF/MS spectral data. Their aggregation properties were investigated in THF by UV-vis and fluorescence. These metal-free and metallophthalocyanine compounds were also evaluated for their total antioxidant abilities by using three different antioxidant methods such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, ferrous ion chelating and reducing power activity. All tested compounds showed radical scavenging activity. The highest radical scavenging activity was found from cobalt phthalocyanine (4) compound respectively. IC50 values of the compounds and standards (BHT and Trolox) were also determined. The results showed that the compound 4 had the highest antioxidant activity among all tested compounds including standards. The tested phthalocyanine compounds had ferrous ion chelating activity. In addition, they showed very high reducing power. All tested compounds had higher reducing power than the standards such as ascorbic acid and BHT. The present study shows that the synthesized tetra phthalocyanine [M: 2H(2), Zn(II)(3), Co(II)(4)] with four peripheral 4-(methylthio) phenoxy compounds have the effective antioxidant properties that can be used as antioxidant agents.

SOD activity and DNA binding properties of a new symmetric porphyrin Schiff base ligand and its metal complexes.

PubMed

Çay, Sevim; Köse, Muhammet; Tümer, Ferhan; Gölcü, Ayşegül; Tümer, Mehmet

2015-12-05

4-Methoxy-2,6-bis(hydroxymethyl)phenol (1) was prepared from the reaction of 4-methoxyphenol and formaldehyde. The compound (1) was then oxidized to the 4-methoxy-2,6-diformylphenol (2) compound. Molecular structure of compound (2) was determined by X-ray diffraction method. A new symmetric porphyrin Schiff base ligand 4-methoxy-2,6-bis[5-(4-iminophenyl)-10,15,20-triphenylporphyrin]phenol (L) was prepared from the reaction of the 5-(4-aminophenyl)-10,15,20-triphenylporphyrin (TTP-NH2) and the compound (2) in the toluene solution. The metal complexes (Cu(II), Fe(III), Mn(III), Pt(II) and Zn(II)) of the ligand (L) were synthesized and characterized by the spectroscopic and analytical methods. The DNA (fish sperm FSdsDNA) binding studies of the ligand and its complexes were performed using UV-vis spectroscopy. Additionally, superoxide dismutase activities of the porphyrin Schiff base metal complexes were investigated. Additionally, electrochemical, photoluminescence and thermal properties of the compounds were investigated. Copyright © 2015 Elsevier B.V. All rights reserved.

Beryllium Metal II. A Review of the Available Toxicity Data

PubMed Central

Strupp, Christian

2011-01-01

Beryllium metal was classified in Europe collectively with beryllium compounds, e.g. soluble salts. Toxicological equivalence was assumed despite greatly differing physicochemical properties. Following introduction of the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) regulation, beryllium metal was classified as individual substance and more investigational efforts to appropriately characterize beryllium metal as a specific substance apart from soluble beryllium compounds was required. A literature search on toxicity of beryllium metal was conducted, and the resulting literature compiled together with the results of a recently performed study package into a comprehensive data set. Testing performed under Organisation for Economic Co-Operation and Development guidelines and Good Laboratory Practice concluded that beryllium metal was neither a skin irritant, an eye irritant, a skin sensitizer nor evoked any clinical signs of acute oral toxicity; discrepancies between the current legal classification of beryllium metal in the European Union (EU) and the experimental results were identified. Furthermore, genotoxicity and carcinogenicity were discussed in the context of the literature data and the new experimental data. It was concluded that beryllium metal is unlikely to be a classical nonthreshold mutagen. Effects on DNA repair and morphological cell transformation were observed but need further investigation to evaluate their relevance in vivo. Animal carcinogenicity studies deliver evidence of carcinogenicity in the rat; however, lung overload may be a species-specific confounding factor in the existing studies, and studies in other species do not give convincing evidence of carcinogenicity. Epidemiology has been intensively discussed over the last years and has the problem that the studies base on the same US beryllium production population and do not distinguish between metal and soluble compounds. It is noted that the correlation between beryllium exposure and carcinogenicity, even including the soluble compounds, remains under discussion in the scientific community and active research is continuing. PMID:21196456

Liquid chromatography coupled to different atmospheric pressure ionization sources-quadrupole-time-of-flight mass spectrometry and post-column addition of metal salt solutions as a powerful tool for the metabolic profiling of Fusarium oxysporum.

PubMed

Cirigliano, Adriana M; Rodriguez, M Alejandra; Gagliano, M Laura; Bertinetti, Brenda V; Godeas, Alicia M; Cabrera, Gabriela M

2016-03-25

Fusarium oxysporum L11 is a non-pathogenic soil-borne fungal strain that yielded an extract that showed antifungal activity against phytopathogens. In this study, reversed-phase high-performance liquid chromatography (RP-HPLC) coupled to different atmospheric pressure ionization sources-quadrupole-time-of-flight mass spectrometry (API-QTOF-MS) was applied for the comprehensive profiling of the metabolites from the extract. The employed sources were electrospray (ESI), atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI). Post-column addition of metal solutions of Ca, Cu and Zn(II) was also tested using ESI. A total of 137 compounds were identified or tentatively identified by matching their accurate mass signals, suggested molecular formulae and MS/MS analysis with previously reported data. Some compounds were isolated and identified by NMR. The extract was rich in cyclic peptides like cyclosporins, diketopiperazines and sansalvamides, most of which were new, and are reported here for the first time. The use of post-column addition of metals resulted in a useful strategy for the discrimination of compound classes since specific adducts were observed for the different compound families. This technique also allowed the screening for compounds with metal binding properties. Thus, the applied methodology is a useful choice for the metabolic profiling of extracts and also for the selection of metabolites with potential biological activities related to interactions with metal ions. Copyright © 2015 Elsevier B.V. All rights reserved.

Generation of low work function, stable compound thin films by laser ablation

DOEpatents

Dinh, Long N.; McLean, II, William; Balooch, Mehdi; Fehring, Jr., Edward J.; Schildbach, Marcus A.

2001-01-01

Generation of low work function, stable compound thin films by laser ablation. Compound thin films with low work function can be synthesized by simultaneously laser ablating silicon, for example, and thermal evaporating an alkali metal into an oxygen environment. For example, the compound thin film may be composed of Si/Cs/O. The work functions of the thin films can be varied by changing the silicon/alkali metal/oxygen ratio. Low work functions of the compound thin films deposited on silicon substrates were confirmed by ultraviolet photoelectron spectroscopy (UPS). The compound thin films are stable up to 500.degree. C. as measured by x-ray photoelectron spectroscopy (XPS). Tests have established that for certain chemical compositions and annealing temperatures of the compound thin films, negative electron affinity (NEA) was detected. The low work function, stable compound thin films can be utilized in solar cells, field emission flat panel displays, electron guns, and cold cathode electron guns.

Reactivity of Metal Oxide Sorbents for Removal of H{sub 2}S

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwon, K.C.; Crowe, E.R.

1996-12-31

Removal of hydrogen sulfide contained in hot coal gases produced from integrated gasification combined cycle power generation systems is required to protect downstream combustion turbines from being corroded with sulfur compounds. Removal of sulfur compounds from hot coal gas products is investigated by using various metal oxide sorbents and membrane separation methods. The main requirements of these metal oxide sorbents are durability and high sulfur loading capacity during absorption-regeneration cycles. In this research, durable metal oxide sorbents were formulated. Reactivity of the formulated metal oxide sorbents with simulated coal gas mixtures was examined to search for an ideal sorbent formulationmore » with a high-sulfur loading capacity suitable for removal of hydrogen sulfide from coal gases. The main objectives of this research are to formulate durable metal oxide sorbents with high-sulfur loading capacity by a physical mixing method, to investigate reaction kinetics on the removal of sulfur compounds from coal gases at high temperature and pressure, to study reaction kinetics on the regeneration of sulfided sorbents, to identify effects of hydrogen partial pressures and moisture on equilibrium/dynamic absorption of hydrogen sulfide into formulated metal oxide sorbents as well as initial reaction rates of H{sub 2}S with formulated metal oxide sorbents, and to evaluate intraparticular diffusivity of H{sub 2}S into formulated sorbents at various reaction conditions. The metal oxide sorbents such as TU-1, TU-19, TU-24, TU-25 and TU-28 were formulated with zinc oxide powder as an active sorbent ingredient, bentonite as a binding material and titanium oxide as a supporting metal oxide.« less

Bioremediation and phytoremediation: Chlorinated and recalcitrant compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1998-12-31

Bioremediation and phytoremediation have progressed, especially with regard to the treatment of hydrocarbon-contaminated sites. Sites contaminated with chlorinated and recalcitrant compounds have proven more resistant to these approaches, but exciting progress is being made both in the laboratory and in the field. This book brings together the latest breakthrough thinking and results in bioremediation, with chapters on cometabolic processes, aerobic and anaerobic mechanisms, biological reductive dechlorination processes, bioaugmentation, biomonitoring, and phytoremediation of recalcitrant organic compounds.

Preparation of cuxinygazsen precursor films and powders by electroless deposition

DOEpatents

Bhattacharya, Raghu N.; Batchelor, Wendi Kay; Wiesner, Holm; Ramanathan, Kannan; Noufi, Rommel

1999-01-01

A method for electroless deposition of Cu.sub.x In.sub.y Ga.sub.z Se.sub.n (x=0-2, y=0-2, z=0-2, n=0-3) precursor films and powders onto a metallic substrate comprising: preparing an aqueous bath solution of compounds selected from the group consisting of: I) a copper compound, a selenium compound, an indium compound and gallium compound; II) a copper compound, a selenium compound and an indium compound; III) a selenium compound, and indium compound and a gallium compound; IV) a selenium compound and a indium compound; and V) a copper compound and selenium compound; each compound being present in sufficient quantity to react with each other to produce Cu.sub.x In.sub.y Ga.sub.z Se.sub.n (x=0-2, y=0-2, z=0-2, n=0-3); adjusting the pH of the aqueous bath solution to an acidic value by the addition of a dilute acid; and initiating an electroless reaction with an oxidizing counterelectrode for a sufficient time to cause a deposit of Cu.sub.x In.sub.y Ga.sub.z Se.sub.n (x=0-2, y=0-2, z=0-2, n=0-3) from the aqueous bath solution onto a metallic substrate.

Isoreticular metal-organic frameworks, process for forming the same, and systematic design of pore size and functionality therein, with application for gas storage

DOEpatents

Yaghi, Omar M.; Eddaoudi, Mohamed; Li, Hailian; Kim, Jaheon; Rosi, Nathaniel

2005-08-16

An isoreticular metal-organic framework (IRMOF) and method for systematically forming the same. The method comprises the steps of dissolving at least one source of metal cations and at least one organic linking compound in a solvent to form a solution; and crystallizing the solution under predetermined conditions to form a predetermined IRMOF. At least one of functionality, dimension, pore size and free volume of the IRMOF is substantially determined by the organic linking compound.

Hair product artifact in magnetic resonance imaging.

PubMed

Chenji, Sneha; Wilman, Alan H; Mah, Dennell; Seres, Peter; Genge, Angela; Kalra, Sanjay

2017-01-01

The presence of metallic compounds in facial cosmetics and permanent tattoos may affect the quality of magnetic resonance imaging. We report a case study describing a signal artifact due to the use of a leave-on powdered hair dye. On reviewing the ingredients of the product, it was found to contain several metallic compounds. In lieu of this observation, we suggest that MRI centers include the use of metal- or mineral-based facial cosmetics or hair products in their screening protocols. Copyright © 2016 Elsevier Inc. All rights reserved.

High surface area graphene-supported metal chalcogenide assembly

DOEpatents

Worsley, Marcus A.; Kuntz, Joshua; Orme, Christine A.

2016-04-19

A composition comprising at least one graphene-supported assembly, which comprises a three-dimensional network of graphene sheets crosslinked by covalent carbon bonds, and at least one metal chalcogenide compound disposed on said graphene sheets, wherein the chalcogen of said metal chalcogenide compound is selected from S, Se and Te. Also disclosed are methods for making and using the graphene-supported assembly, including graphene-supported MoS.sub.2. Monoliths with high surface area and conductivity can be achieved. Lower operating temperatures in some applications can be achieved. Pore size and volume can be tuned.

Method for preparing a thick film conductor

DOEpatents

Nagesh, Voddarahalli K.; Fulrath, deceased, Richard M.

1978-01-01

A method for preparing a thick film conductor which comprises providing surface active glass particles, mixing the surface active glass particles with a thermally decomposable organometallic compound, for example, a silver resinate, and then decomposing the organometallic compound by heating, thereby chemically depositing metal on the glass particles. The glass particle mixture is applied to a suitable substrate either before or after the organometallic compound is thermally decomposed. The resulting system is then fired in an oxidizing atmosphere, providing a microstructure of glass particles substantially uniformly coated with metal.

Magnetic moment in single crystalline BaFe2-xZnxAs2

NASA Astrophysics Data System (ADS)

Guo, Yanfeng; Wang, Xia; Li, Jun; Yamaura, Kazunari; Takayama-Muromachi, Eiji

2012-02-01

Nature of the magnetism for iron-based superconductors (FeSCs) has been actively studied since the discovery of this new family of compounds in 2008, largely owing to its significance for interpreting the paring mechanism. The approach through impurity substitution to shed light into this issue is always one of major ways. The substitution shows distinct responses to species of impurities, where partially replacement of Fe in parent FeSCs with a variety of d-metals like Co, Ni Ru, Rh, Pd, Ir, and Pt generally results in superconductivity, while recent progress in Zn doped FeSCs gives rather contrary result, where Zn severely degenerates the TC. Herein we show the magnetic and electrical studies on BaFe2-xZnxAs2 single crystals. Nonmagnetic Zn doping progressively suppresses the SDW without resulting in superconductivity, while it alternatively develops the spin-glass state, possibly suggestive of local magnetic moment around the Fe sites induced by Zn. The characterizations by X-ray diffraction, magnetic and electrical transport properties, specific heat capacity, and Hall coefficient have been done and the results will be discussed in detail.

Cross-linking proteins with bimetallic tetracarboxylate compounds of transition metals

DOEpatents

Kostic, N.M.; Chen, J.

1991-03-05

Stable cross-linked complexes of transition-metal tetracarboxylates and proteins are formed. The preferred transition-metal is rhodium. The protein may be collagen or an enzyme such as a proteolytic enzyme. No Drawings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdellahi, Aziz; Urban, Alexander; Dacek, Stephen

Cation disorder is a phenomenon that is becoming increasingly important for the design of high-energy lithium transition metal oxide cathodes (LiMO 2) for Li-ion batteries. Disordered Li-excess rocksalts have recently been shown to achieve high reversible capacity, while in operando cation disorder has been observed in a large class of ordered compounds. The voltage slope (dV/dx u )is a critical quantity for the design of cation-disordered rocksalts, as it controls the Li capacity accessible at voltages below the stability limit of the electrolyte (~4.5-4.7 V). In this study, we develop a lattice model based on first principles to understand andmore » quantify the voltage slope of cation-disordered LiMO 2. We show that cation disorder increases the voltage slope of Li transition metal oxides by creating a statistical distribution of transition metal environments around Li sites, as well as by allowing Li occupation of highvoltage tetrahedral sites. We further demonstrate that the voltage slope increase upon disorder is generally smaller for highvoltage transition metals than for low-voltage transition metals due to a more effective screening of Li-M interactions by oxygen electrons. Short-range order in practical disordered compounds is found to further mitigate the voltage slope increase upon disorder. In conclusion, our analysis shows that the additional high-voltage tetrahedral capacity induced by disorder is smaller in Liexcess compounds than in stoichiometric LiMO 2 compounds.« less

Magnetic-field-induced effects in the electronic structure of itinerant d- and f-metal systems

NASA Astrophysics Data System (ADS)

Grechnev, G. E.

2009-08-01

A paramagnetic response of transition metals and itinerant d- and f-metal compounds in an external magnetic field is studied by employing ab initio full-potential LMTO method in the framework of the local spin density approximation. Within this method the anisotropy of the magnetic susceptibility in hexagonal close-packed transition metals is evaluated for the first time. This anisotropy is owing to the orbital Van Vleck-like paramagnetic susceptibility, which is revealed to be substantial in transition-metal systems due to hybridization effects in the electronic structure. It is demonstrated that compounds TiCo, Ni3Al, YCo2, CeCo2, YNi5, LaNi5, and CeNi5 are strong paramagnets close to the quantum critical point. For these systems the Stoner approximation underestimates the spin susceptibility, whereas the calculated field-induced spin moments provide a good description of the large paramagnetic susceptibilities and magnetovolume effects. It is revealed that an itinerant description of hybridized f electrons produces magnetic properties of the compounds CeCo2, CeNi5, UAl3, UGa3, USi3, and UGe3 in close agreement with experiment. In the uranium compounds UX3 the strong spin-orbit coupling together with hybridization effects give rise to peculiar magnetic states in which the field-induced spin moments are antiparallel to the external field, and the magnetic response is dominated by the orbital contribution.

A Review on Recent Advances in the Application of Nanocatalysts in A3 Coupling Reactions.

PubMed

Nasrollahzadeh, Mahmoud; Sajjadi, Mohaddeseh; Ghorbannezhad, Fatemeh; Sajadi, S Mohammad

2018-03-14

A 3 coupling is one of the few transition-metal catalyzed carbon-carbon bond forming reactions that have been established as a most direct, efficient and atom-economical synthetic approach to afford propargylamine derivatives using various catalysts. A large number of nanosized heterogeneous catalysts for three-component coupling reactions between an aldehyde, an amine, and a terminal alkyne have been popularly introduced as an A 3 coupling in the last decade. The coupling product has found a broad application as a key intermediate for a variety of heterocyclic useful compounds and numerous biologically active molecules such as β-lactams, conformationally restricted peptides, isosteres, herbicides, fungicides, indolizines, pyrroles, quinolines and therapeutic drug molecules. This review aims to give an overview of the current progress made towards the preparation and application of various nanocatalysts-catalyzed A 3 coupling transformations for the synthesis of propargylamines from 2007 to 2017. Several nanocatalysts based on metal and metal oxide nanoparticles (NPs) such as copper, gold, silver, iron, nickel, cobalt and zinc have successfully been employed in A 3 coupling reactions. Besides, core-shells NPs, polymers, complexes, graphenes, metal-organic frameworks and ionic liquids have also been used in these reactions. Abundant examples have been given in this area. Different aspects of the reactions, disparate methods of preparation of nanocatalysts, characterization and their reusability have been perused. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method for producing refractory nitrides

DOEpatents

Quinby, Thomas C.

1989-01-24

A process for making fine, uniform metal nitride powders that can be hot pressed or sintered. A metal salt is placed in a solvent with Melamine and warmed until a metal-Melamine compound forms. The solution is cooled and the metal-Melamine precipitate is calcined at a temperature below 700.degree. C. to form the metal nitrides and to avoid formation of the metal oxide.

Method for producing nanocrystalline multicomponent and multiphase materials

DOEpatents

Eastman, J.A.; Rittner, M.N.; Youngdahl, C.J.; Weertman, J.R.

1998-03-17

A process for producing multi-component and multiphase nanophase materials is provided wherein a plurality of elements are vaporized in a controlled atmosphere, so as to facilitate thorough mixing, and then condensing and consolidating the elements. The invention also provides for a multicomponent and multiphase nanocrystalline material of specified elemental and phase composition having component grain sizes of between approximately 1 nm and 100 nm. This material is a single element in combination with a binary compound. In more specific embodiments, the single element in this material can be a transition metal element, a non-transition metal element, a semiconductor, or a semi-metal, and the binary compound in this material can be an intermetallic, an oxide, a nitride, a hydride, a chloride, or other compound. 6 figs.

Ultrahigh Ionic Conduction in Water-Stable Close-Packed Metal-Carbonate Frameworks.

PubMed

Manna, Biplab; Desai, Aamod V; Illathvalappil, Rajith; Gupta, Kriti; Sen, Arunabha; Kurungot, Sreekumar; Ghosh, Sujit K

2017-08-21

Utilization of the robust metal-carbonate backbone in a series of water-stable, anionic frameworks has been harnessed for the function of highly efficient solid-state ion-conduction. The compact organization of hydrophilic guest ions facilitates water-assisted ion-conduction in all the compounds. The dense packing of the compounds imparts high ion-conducting ability and minimizes the possibility of fuel crossover, making this approach promising for design and development of compounds as potential components of energy devices. This work presents the first report of evaluating ion-conduction in a purely metal-carbonate framework, which exhibits high ion-conductivity on the order of 10 -2 S cm -1 along with very low activation energy, which is comparable to highly conducting well-known crystalline coordination polymers or commercialized organic polymers like Nafion.

Direct synthesis of catalyzed hydride compounds

DOEpatents

Gross, Karl J.; Majzoub, Eric

2004-09-21

A method is disclosed for directly preparing alkali metal aluminum hydrides such as NaAlH.sub.4 and Na.sub.3 AlH.sub.6 from either the alkali metal or its hydride, and aluminum. The hydride thus prepared is doped with a small portion of a transition metal catalyst compound, such as TiCl.sub.3, TiF.sub.3, or a mixture of these materials, in order to render them reversibly hydridable. The process provides for mechanically mixing the dry reagents under an inert atmosphere followed by charging the mixed materials with high pressure hydrogen while heating the mixture to about 125.degree. C. The method is relatively simple and inexpensive and provides reversible hydride compounds which are free of the usual contamination introduced by prior art wet chemical methods.

A functional applied material on recognition of metal ion zinc based on the double azine compound.

PubMed

Wei, Taibao; Liang, Guoyan; Chen, Xiaopeng; Qi, Jin; Lin, Qi; Zhang, Youming; Yao, Hong

2017-05-18

A colorimetric and fluorescent probe L has been designed and synthesized, which bearing the double azine moiety and showing a detection limit of 2.725 × 10 -7  M towards Zn 2+ . Based on the basic recognition mechanism of ESIPT and CHEF effect, the L has high selectivity and sensitivity to only Zn 2+ (not Fe 3+ , Hg 2+ , Ag + , Ca 2+ , Co 2+ , Ni 2+ , Cd 2+ , Pb 2+ , Cr 3+ , and Mg 2+ ) within the physiological pH range (pH = 7.0-8.4) and showed a fluorescence switch. Moreover, this detection progress occured in the DMSO/H 2 O ∼ HEPES buffer (80/20, v/v; pH 7.23) solution which can conveniently used on test strip.

Recent progress in the development of a SPARROW model of sediment for the conterminous U.S.

USGS Publications Warehouse

Schwarz, Gregory; Smith, Richard; Alexander, Richard; Gray, John

2003-01-01

Suspended sediment has long been recognized as an important contaminant affecting water resources. Besides its direct role in determining water clarity, bridge scour and reservoir storage, sediment serves as a vehicle for the transport of many binding contaminants, including nutrients, trace metals, semi- volatile organic compounds, and numerous pesticides (U.S. Environmental Protection Agency 2000a). Recent efforts to address water quality concerns through the TMDL process have identified sediment as the single most prevalent cause of impairment in the Nation’s streams and rivers (U.S. Environmental Protection Agency 2000b). Moreover, sediment has been identified as a medium for the transport and sequestration of organic carbon, playing a potentially important role in understanding sources and sinks in the global carbon budget (Stallard 1998).

Direct synthesis of calcium borohydride

DOEpatents

Ronnebro, Ewa Carin Ellinor [Dublin, CA; Majzoub, Eric H [Pleasanton, CA

2009-10-27

A method is disclosed for directly preparing an alkaline earth metal borohydride, i.e. Ca(BH.sub.4).sub.2, from the alkaline earth metal hydride and the alkaline earth metal boride. The borohydride thus prepared is doped with a small portion of a metal chloride catalyst compound, such as RuCl.sub.3, TiCl.sub.3, or a mixture of TiCl.sub.3 and palladium metal. The process provides for mechanically mixing the dry reagents under an inert atmosphere followed by charging the mixed materials with high pressure hydrogen at about 70 MPa while heating the mixture to about 400.degree. C. The method is relatively simple and inexpensive and provides reversible hydride compounds which are free of the usual contamination introduced by prior art wet chemical methods.

Organometallic chemistry of heterobimetallic compounds: Final report for the period August 1, 1985-June 30, 1988

DOE Office of Scientific and Technical Information (OSTI.GOV)

Casey, C.P.

1988-03-01

Work is reported on the following: formyl compounds, cyclopentadienyl ring slippage, ..mu..-hydrocarbyl diiron complexes, heterobimetallic compounds linked by heterodifunctional ligands, heterobimetallic dihydrides, reactions of heterobimetallic dihydrides, early-late transition metal bimetallic compounds, and heterobimetallic ..mu..-alkylidene complexes. (DLC)

Membrane extraction with thermodynamically unstable diphosphonic acid derivatives

DOEpatents

Horwitz, E.P.; Gatrone, R.C.; Nash, K.L.

1997-10-14

Thermodynamically-unstable complexing agents which are diphosphonic acids and diphosphonic acid derivatives (or sulphur containing analogs), like carboxyhydroxymethanediphosphonic acid and vinylidene-1,1-diphosphonic acid, are capable of complexing with metal ions, and especially metal ions in the II, III, IV, V and VI oxidation states, to form stable, water-soluble metal ion complexes in moderately alkaline to highly-acidic media. However, the complexing agents can be decomposed, under mild conditions, into non-organic compounds which, for many purposes are environmentally-nondamaging compounds thereby degrading the complex and releasing the metal ion for disposal or recovery. Uses for such complexing agents as well as methods for their manufacture are also described. 1 fig.

Computational investigation of half-Heusler compounds for spintronics applications

NASA Astrophysics Data System (ADS)

Ma, Jianhua; Hegde, Vinay I.; Munira, Kamaram; Xie, Yunkun; Keshavarz, Sahar; Mildebrath, David T.; Wolverton, C.; Ghosh, Avik W.; Butler, W. H.

2017-01-01

We present first-principles density functional calculations of the electronic structure, magnetism, and structural stability of 378 XYZ half-Heusler compounds (with X = Cr, Mn, Fe, Co, Ni, Ru, Rh; Y = Ti, V, Cr, Mn, Fe, Ni; Z = Al, Ga, In, Si, Ge, Sn, P, As, Sb). We find that a "Slater-Pauling gap" in the density of states (i.e., a gap or pseudogap after nine states in the three atom primitive cell) in at least one spin channel is a common feature in half-Heusler compounds. We find that the presence of such a gap at the Fermi energy in one or both spin channels contributes significantly to the stability of a half-Heusler compound. We calculate the formation energy of each compound and systematically investigate its stability against all other phases in the open quantum materials database (OQMD). We represent the thermodynamic phase stability of each compound as its distance from the convex hull of stable phases in the respective chemical space and show that the hull distance of a compound is a good measure of the likelihood of its experimental synthesis. We find low formation energies and mostly correspondingly low hull distances for compounds with X = Co, Rh, or Ni, Y = Ti or V, and Z = P, As, Sb, or Si. We identify 26 18-electron semiconductors, 45 half-metals, and 34 near half-metals with negative formation energy that follow the Slater-Pauling rule of three electrons per atom. Our calculations predict several new, as-yet unknown, thermodynamically stable phases, which merit further experimental exploration—RuVAs, CoVGe, FeVAs in the half-Heusler structure, and NiScAs, RuVP, RhTiP in the orthorhombic MgSrSi-type structure. Further, two interesting zero-moment half-metals, CrMnAs and MnCrAs, are calculated to have negative formation energy. In addition, our calculations predict a number of hitherto unreported semiconducting (e.g., CoVSn and RhVGe), half-metallic (e.g., RhVSb), and near half-metallic (e.g., CoFeSb and CoVP) half-Heusler compounds to lie close to the respective convex hull of stable phases, and thus may be experimentally realized under suitable synthesis conditions, resulting in potential candidates for various semiconducting and spintronics applications.

Homeostasis of metals in the progression of Alzheimer's disease.

PubMed

González-Domínguez, Raúl; García-Barrera, Tamara; Gómez-Ariza, José Luis

2014-06-01

In order to study the involvement of metals in the progression of Alzheimer's disease, serum samples from patients with Alzheimer and mild cognitive impairment were investigated. For this purpose, metal content was analyzed after size-fractionation of species and then, inter-element and inter-fraction ratios were computed. In this way, the analysis allowed discovering changes that could be used as markers of disease, but also provided a new insight into the interactions in the homeostasis of elements in neurodegeneration and its progression. Aluminum and labile forms of iron and copper were increased in demented patients, while manganese, zinc and selenium were reduced. Interestingly, levels of different elements, principally iron, aluminum and manganese, were closely inter-related, which could evidence a complex interdependency between the homeostasis of the different metals in this disorder. On the other hand, imbalances in metabolism of copper, zinc and selenium could be associated to abnormal redox status. Therefore, this study may contribute to our understanding of the pathological mechanisms related to metals in Alzheimer's disease.

Harnessing redox activity for the formation of uranium tris(imido) compounds

NASA Astrophysics Data System (ADS)

Anderson, Nickolas H.; Odoh, Samuel O.; Yao, Yiyi; Williams, Ursula J.; Schaefer, Brian A.; Kiernicki, John J.; Lewis, Andrew J.; Goshert, Mitchell D.; Fanwick, Phillip E.; Schelter, Eric J.; Walensky, Justin R.; Gagliardi, Laura; Bart, Suzanne C.

2014-10-01

Classically, late transition-metal organometallic compounds promote multielectron processes solely through the change in oxidation state of the metal centre. In contrast, uranium typically undergoes single-electron chemistry. However, using redox-active ligands can engage multielectron reactivity at this metal in analogy to transition metals. Here we show that a redox-flexible pyridine(diimine) ligand can stabilize a series of highly reduced uranium coordination complexes by storing one, two or three electrons in the ligand. These species reduce organoazides easily to form uranium-nitrogen multiple bonds with the release of dinitrogen. The extent of ligand reduction dictates the formation of uranium mono-, bis- and tris(imido) products. Spectroscopic and structural characterization of these compounds supports the idea that electrons are stored in the ligand framework and used in subsequent reactivity. Computational analyses of the uranium imido products probed their molecular and electronic structures, which facilitated a comparison between the bonding in the tris(imido) structure and its tris(oxo) analogue.

First-order metal-insulator transitions in vanadates from first principles

NASA Astrophysics Data System (ADS)

Kumar, Anil; Rabe, Karin

2013-03-01

Materials that exhibit first-order metal-insulator transitions, with the accompanying abrupt change in the conductivity, have potential applications as switches in future electronic devices. Identification of materials and exploration of the atomic-scale mechanisms for switching between the two electronic states is a focus of current research. In this work, we search for first-order metal-insulator transitions in transition metal compounds, with a particular focus on d1 and d2 systems, by using first principles calculations to screen for an alternative low-energy state having not only a electronic character opposite to that of the ground state, but a distinct structure and/or magnetic ordering which would permit switching by an applied field or stress. We will present the results of our investigation of the perovskite compounds SrVO3, LaVO3, CaVO3, YVO3, LaTiO3 and related layered phase, including superlattices and Ruddlesden-Popper phases. While the pure compounds do not satisfy the search criteria, the layered phases show promising results.

Surfactant-thermal method to prepare two new cobalt metal-organic frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Xianglin; Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430074; Toh, Yong Siang

2015-12-15

Employing surfactants as reaction media, two new metal-organic frameworks (MOFs):(HTEA){sub 3}[Co{sub 3}(BTC){sub 3}] (NTU-Z33) and (HTEA)[Co{sub 3}(HBTC){sub 2}(BTC)] (NTU-Z34) (H{sub 3}BTC=1,3,5-benzenetricarboxylic acid, TEA=trimethylamine, and NTU=Nanyang Technological University), have been successfully synthesized and fully characterized. Note that NTU-Z33 has an unusual trimeric [Co{sub 3}(COO){sub 9}] secondary building unit (SBU). Magnetic characterization suggests that both compounds have weak antiferromagnetic behaviors. Our success in preparing new crystalline Co-BTC based MOFs under different surfactant media could provide a new road to prepare new diverse MOFs through various combinations of surfactants. - Graphical abstract: Employing surfactants as reaction media, two new metal-organic frame-works (MOFs) havemore » been successfully synthesized and magnetic study suggests that both compounds have weak antiferromagnetic behaviors. - Highlights: • Two novel metal-organic frame-works (MOFs). • Synthesis through surfactant-thermal condition. • weak antiferromagnetic behaviors for both compounds.« less

Betula pendula: A Promising Candidate for Phytoremediation of TCE in Northern Climates.

PubMed

Lewis, Jeffrey; Qvarfort, Ulf; Sjöström, Jan

2015-01-01

Betula pendula (Silver birch) trees growing on two contaminated sites were evaluated to assess their capacity to phytoscreen and phytoremediate chlorinated aliphatic compounds and heavy metals. Both locations are industrially-contaminated properties in central Sweden. The first was the site of a trichloroethylene (TCE) spill in the 1980s while the second was polluted with heavy metals by burning industrial wastes. In both cases, sap and sapwood from Silver birch trees were collected and analyzed for either chlorinated aliphatic compounds or heavy metals. These results were compared to analyses of the surface soil, vadose zone pore air and groundwater. Silver birch demonstrated the potential to phytoscreen and possibly phytoremediate TCE and related compounds, but it did not demonstrate the ability to effectively phytoextract heavy metals when compared with hyperaccumulator plants. The capacity of Silver birch to phytoremediate TCE appears comparable to tree species that have been employed in field-scale TCE phytoremediation efforts, such as Populus spp. and Eucalyptus sideroxylon rosea.

Facile scission of isonitrile carbon–nitrogen triple bond using a diborane(4) reagent

PubMed Central

Asakawa, Hiroki; Lee, Ka-Ho; Lin, Zhenyang; Yamashita, Makoto

2014-01-01

Transition metal reagents and catalysts are generally effective to cleave all three bonds (one σ and two π) in a triple bond despite its high bonding energy. Recently, chemistry of single-bond cleavage by using main-group element compounds is rapidly being developed in the absence of transition metals. However, the cleavage of a triple bond using non-transition-metal compounds is less explored. Here we report that an unsymmetrical diborane(4) compound could react with carbon monoxide and tert-butyl isonitrile at room temperature. In the latter case, the carbon–nitrogen triple bond was completely cleaved in the absence of transition metal as confirmed by X-ray crystallographic analysis, 13C NMR spectroscopy with 13C labelling and DFT calculations. The DFT calculations also revealed the detailed reaction mechanism and indicated that the key for the carbon–nitrogen triple-bond cleavage could be attributed to the presence of nucleophilic nitrogen atom in one of the intermediates. PMID:24967910

Discovery of novel PDE9 inhibitors capable of inhibiting Aβ aggregation as potential candidates for the treatment of Alzheimer's disease.

PubMed

Su, Tao; Zhang, Tianhua; Xie, Shishun; Yan, Jun; Wu, Yinuo; Li, Xingshu; Huang, Ling; Luo, Hai-Bin

2016-02-25

Recently, phosphodiesterase-9 (PDE9) inhibitors and biometal-chelators have received much attention as potential therapeutics for the treatment of Alzheimer's disease (AD). Here, we designed, synthesized, and evaluated a novel series of PDE9 inhibitors with the ability to chelate metal ions. The bioassay results showed that most of these molecules strongly inhibited PDE9 activity. Compound 16 showed an IC50 of 34 nM against PDE9 and more than 55-fold selectivity against other PDEs. In addition, this compound displayed remarkable metal-chelating capacity and a considerable ability to halt copper redox cycling. Notably, in comparison to the reference compound clioquinol, it inhibited metal-induced Aβ(1-42) aggregation more effectively and promoted greater disassembly of the highly structured Aβ fibrils generated through Cu(2+)-induced Aβ aggregation. These activities of 16, together with its favorable blood-brain barrier permeability, suggest that 16 may be a promising compound for treatment of AD.

Inter-laboratory assessment of a harmonized zebrafish developmental toxicology assay - progress report on phase I.

PubMed

Gustafson, A-L; Stedman, D B; Ball, J; Hillegass, J M; Flood, A; Zhang, C X; Panzica-Kelly, J; Cao, J; Coburn, A; Enright, B P; Tornesi, M B; Hetheridge, M; Augustine-Rauch, K A

2012-04-01

This report provides a progress update of a consortium effort to develop a harmonized zebrafish developmental toxicity assay. Twenty non-proprietary compounds (10 animal teratogens and 10 animal non-teratogens) were evaluated blinded in 4 laboratories. Zebrafish embryos from pond-derived and cultivated strain wild types were exposed to the test compounds for 5 days and subsequently evaluated for lethality and morphological changes. Each of the testing laboratories achieved similar overall concordance to the animal data (60-70%). Subsequent optimization procedures to improve the overall concordance focused on compound formulation and test concentration adjustments, chorion permeation and number of replicates. These optimized procedures were integrated into a revised protocol and all compounds were retested in one lab using embryos from pond-derived zebrafish and achieved 85% total concordance. To further assess assay performance, a study of additional compounds is currently in progress at two laboratories using embryos from pond-derived and cultivated-strain wild type zebrafish. Copyright © 2011 Elsevier Inc. All rights reserved.

[Regulation of sulfates, hydrogen sulfide and heavy metals in technogenic reservoirs by sulfate-reducing bacteria].

PubMed

Hudz', S P; Peretiatko, T B; Moroz, O M; Hnatush, S O; Klym, I R

2011-01-01

Sulfate-reducing bacteria Desulfovibrio desulfuricans Ya-11 in the presence of sulfates and organic compounds in the medium reduce sulfates to hydrogen sulfide (dissimilatory sulfate reduction). Heavy metals in concentration over 2 mM inhibit this process. Pb2+, Zn2+, Ni2+, Co2+, Fe2+ and Cd2+ ions in concentration 1-1.5 mM display insignificant inhibiting effect on sulfate reduction process, and metals precipitate in the form of sulfides. At concentrations of heavy metals 2-3 mM one can observe a decrease of sulfates reduction intensity, and a percent of metals binding does not exceed 72%. Obtained results give reason to confirm, that sulfate-reducing bacteria play an important role in regulation of the level of sulfates, hydrogen sulfide and heavy metals in reservoirs and they may be used for purification of water environment from these compounds.

Bridged transition-metal complexes and uses thereof for hydrogen separation, storage and hydrogenation

DOEpatents

Lilga, Michael A.; Hallen, Richard T.

1990-01-01

The present invention constitutes a class of organometallic complexes which reversibly react with hydrogen to form dihydrides and processes by which these compounds can be utilized. The class includes bimetallic complexes in which two cyclopentadienyl rings are bridged together and also separately .pi.-bonded to two transition metal atoms. The transition metals are believed to bond with the hydrogen in forming the dihydride. Transition metals such as Fe, Mn or Co may be employed in the complexes although Cr constitutes the preferred metal. A multiple number of ancilliary ligands such as CO are bonded to the metal atoms in the complexes. Alkyl groups and the like may be substituted on the cyclopentadienyl rings. These organometallic compounds may be used in absorption/desorption systems and in facilitated transport membrane systems for storing and separating out H.sub.2 from mixed gas streams such as the produce gas from coal gasification processes.

Bridged transition-metal complexes and uses thereof for hydrogen separation, storage and hydrogenation

DOEpatents

Lilga, M.A.; Hallen, R.T.

1991-10-15

The present invention constitutes a class of organometallic complexes which reversibly react with hydrogen to form dihydrides and processes by which these compounds can be utilized. The class includes bimetallic complexes in which two cyclopentadienyl rings are bridged together and also separately [pi]-bonded to two transition metal atoms. The transition metals are believed to bond with the hydrogen in forming the dihydride. Transition metals such as Fe, Mn or Co may be employed in the complexes although Cr constitutes the preferred metal. A multiple number of ancillary ligands such as CO are bonded to the metal atoms in the complexes. Alkyl groups and the like may be substituted on the cyclopentadienyl rings. These organometallic compounds may be used in absorption/desorption systems and in facilitated transport membrane systems for storing and separating out H[sub 2] from mixed gas streams such as the product gas from coal gasification processes. 3 figures.

Bridged transition-metal complexes and uses thereof for hydrogen separation, storage and hydrogenation

DOEpatents

Lilga, M.A.; Hallen, R.T.

1990-08-28

The present invention constitutes a class of organometallic complexes which reversibly react with hydrogen to form dihydrides and processes by which these compounds can be utilized. The class includes bimetallic complexes in which two cyclopentadienyl rings are bridged together and also separately [pi]-bonded to two transition metal atoms. The transition metals are believed to bond with the hydrogen in forming the dihydride. Transition metals such as Fe, Mn or Co may be employed in the complexes although Cr constitutes the preferred metal. A multiple number of ancillary ligands such as CO are bonded to the metal atoms in the complexes. Alkyl groups and the like may be substituted on the cyclopentadienyl rings. These organometallic compounds may be used in absorption/desorption systems and in facilitated transport membrane systems for storing and separating out H[sub 2] from mixed gas streams such as the producer gas from coal gasification processes. 3 figs.

Bridged transition-metal complexes and uses thereof for hydrogen separation, storage and hydrogenation

DOEpatents

Lilga, Michael A.; Hallen, Richard T.

1991-01-01

The present invention constitutes a class of organometallic complexes which reversibly react with hydrogen to form dihydrides and processes by which these compounds can be utilized. The class includes bimetallic complexes in which two cyclopentadienyl rings are bridged together and also separately .pi.-bonded to two transition metal atoms. The transition metals are believed to bond with the hydrogen in forming the dihydride. Transition metals such as Fe, Mn or Co may be employed in the complexes although Cr constitutes the preferred metal. A multiple number of ancilliary ligands such as CO are bonded to the metal atoms in the complexes. Alkyl groups and the like may be substituted on the cyclopentadienyl rings. These organometallic compounds may be used in absorption/desorption systems and in facilitated transport membrane systems for storing and separating out H.sub.2 from mixed gas streams such as the product gas from coal gasification processes.

Determination of theoretical capacity of metal ion-doped LiMn 2O 4 as the positive electrode in Li-ion batteries

NASA Astrophysics Data System (ADS)

Todorov, Yanko M.; Hideshima, Yasufumi; Noguchi, Hideyuki; Yoshio, Masaki

The theoretical capacity and cation vacancy of metal ion (M)-doped LiMn 2- xM xO 4 spinel compounds serving as positive electrodes in a 4-V lithium ion batteries are calculated. The capacity depends strongly on the mole fraction of doped metal ion and vacancies. The theoretical capacity increases with increasing oxidation number of the doped metal ion in the 16d site of LiMn 2O 4 at the same doping fraction. The validity of the proposed equation for calculation of the capacity has been initially confirmed using a metal ion with well-known valence, such as the Al ion. The oxidation state of Co, Ni and Cr ions in the spinel structure is found to be trivalent, divalent and trivalent, respectively. Analysis shows that metal ion-doped spinel compounds with low vacancy content promote high capacity.

Synthesis and molecular structures of phenylamides of magnesium, calcium, strontium, and barium--from molecular to polymeric structures.

PubMed

Gärtner, Martin; Görls, Helmar; Westerhausen, Matthias

2007-09-03

Several preparative procedures for the synthesis of the THF complexes of the alkaline earth metal bis(phenylamides) of Mg (1), Ca (2), Sr (3), and Ba (4) are presented such as metalation of aniline with strontium and barium, metathesis reactions of MI2 with KN(H)Ph, and metalation of aniline with arylcalcium compounds or dialkylmagnesium. The THF content of these compounds is rather low and an increasing aggregation is observed with the size of the metal atom. Thus, tetrameric [(THF)2Ca{mu-N(H)Ph}2]4 (2) and polymeric [(THF)2Sr{mu-N(H)Ph}2]infinity and {[(THF)2Ba{mu-N(H)Ph}2]2[(THF)Ba{mu-N(H)Ph}2]2}infinity show six-coordinate metal atoms with increasing interactions to the pi systems of the phenyl groups with increasing the radius of the alkaline earth metal atom.

Impact of Heavy Metal Pollution on Ammonia Oxidizers in Soils in the Vicinity of a Tailings Dam, Baotou, China.

PubMed

Liu, Jumei; Cao, Weiwei; Jiang, Haiming; Cui, Jing; Shi, Chunfang; Qiao, Xiaohui; Zhao, Ji; Si, Wantong

2018-05-09

Soil heavy metal pollution has received increasing attention due to their toxicity to soil microorganisms. We have analyzed the effects of heavy metal pollution on ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in soils in the vicinity of a tailings dam of Baotou region, China. Results showed that AOB were dominated with Nitrosomonas-like clusters, while AOA was dominated by group1.1b (Nitrososphaera cluster). Single Cd and Cr contents, as well as compound heavy metal pollution levels, had a significant negative impact on soil potential nitrification rate and both diversities of AOA and AOB. No clear relationship was found between any single heavy metal and abundance of AOA or AOB. But compound pollution could significantly decrease AOA abundance. The results indicated that heavy metal pollution had an obviously deleterious effect on the abundance, diversity, activity and composition of ammonia oxidizers in natural soils.

Hydroxyalkyl phosphine compounds for use as diagnostic and therapeutic pharmaceuticals

DOEpatents

Katti, K.V.; Singh, P.R.; Reddy, V.S.; Katti, K.K.; Volkert, W.A.; Ketring, A.R.

1999-03-02

This research discloses a compound and method of making a compound for use as a diagnostic or therapeutic pharmaceutical comprises a functionalized hydroxyalkyl phosphine ligand and a metal combined with the ligand. 16 figs.

Metal hydride compositions and lithium ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, Kwo; Nei, Jean

Heterogeneous metal hydride (MH) compositions comprising a main region comprising a first metal hydride and a secondary region comprising one or more additional components selected from the group consisting of second metal hydrides, metals, metal alloys and further metal compounds are suitable as anode materials for lithium ion cells. The first metal hydride is for example MgH.sub.2. Methods for preparing the composition include coating, mechanical grinding, sintering, heat treatment and quenching techniques.

Plant growth promotion, metabolite production and metal tolerance of dark septate endophytes isolated from metal-polluted poplar phytomanagement sites.

PubMed

Berthelot, Charlotte; Leyval, Corinne; Foulon, Julie; Chalot, Michel; Blaudez, Damien

2016-10-01

Numerous studies address the distribution and the diversity of dark septate endophytes (DSEs) in the literature, but little is known about their ecological role and their effect on host plants, especially in metal-polluted soils. Seven DSE strains belonging to Cadophora, Leptodontidium, Phialophora and Phialocephala were isolated from roots of poplar trees from metal-polluted sites. All strains developed on a wide range of carbohydrates, including cell-wall-related compounds. The strains evenly colonized birch, eucalyptus and ryegrass roots in re-synthesis experiments. Root and shoot growth promotion was observed and was both plant and strain dependent. Two Phialophora and Leptodontidium strains particularly improved plant growth. However, there was no correlation between the level of root colonization by DSEs and the intensity of growth promotion. All strains produced auxin and six also stimulated plant growth through the release of volatile organic compounds (VOCs). SPME-GC/MS analyses revealed four major VOCs emitted by Cadophora and Leptodontidium The strains exhibited growth at high concentrations of several metals. The ability of metal-resistant DSE strains to produce both soluble and volatile compounds for plant growth promotion indicates interesting microbial resources with high potential to support sustainable production of bioenergy crops within the context of the phytomanagement of metal-contaminated sites. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

SR-XRD and SR-FTIR study of the alteration of silver foils in medieval paintings.

PubMed

Salvadó, Nati; Butí, Salvador; Labrador, Ana; Cinque, Gianfelice; Emerich, Hermann; Pradell, Trinitat

2011-03-01

Altarpieces and polychrome carved wood from the fifteenth century AD usually exhibit golden and silvery areas by the application of a very thin foil of metal. The metal foils were normally protected from the atmosphere by a varnish or resin which maybe either preserved or absent. Moreover, they were glued to the background surface by adhesive substances (egg yolk, drying oil or animal glue). The high proportion of the glueing substances often renders the development of reaction compounds. With time, silver alters blacken or simply disappear completely. In this paper, we study the alterations to metal foils from a selection of fifteenth century artworks showing different glueing agents, organic coatings and several degrees of conservation of the organic coatings and metal leafs. The submillimetric layered structure and the high variability and low amount of most of the compounds present in the different layers, as well as their differing nature (organic and inorganic) make the use of micron-sensitive high-resolution techniques essential for their study. In particular, the high resolution, high brilliance and small footprint renders synchrotron radiation most adequate for their study. SR-XRD was performed to identify the reaction compounds formed in the different layers; μFTIR was used at to identify the silver protecting organic coatings, the metal foil glueing layers and the corresponding reaction compounds. The results obtained suggest that atmospheric corrosion is the dominant mechanism, and therefore that the degree of corrosion of the metal foils is mainly related to the conservation state of the protecting coatings.

Carbon based secondary compounds do not provide protection against heavy metal road pollutants in epiphytic macrolichens.

PubMed

Gauslaa, Yngvar; Yemets, Olena A; Asplund, Johan; Solhaug, Knut Asbjørn

2016-01-15

Lichens are useful monitoring organisms for heavy metal pollution. They are high in carbon based secondary compounds (CBSCs) among which some may chelate heavy metals and thus increase metal accumulation. This study quantifies CBSCs in four epiphytic lichens transplanted for 6months on stands along transects from a highway in southern Norway to search for relationships between concentrations of heavy metals and CBSCs along a gradient in heavy metal pollutants. Viability parameters and concentrations of 21 elements including nutrients and heavy metals in these lichen samples were reported in a separate paper. Medullary CBSCs in fruticose lichens (Ramalina farinacea, Usnea dasypoga) were reduced in the most polluted sites, but not in foliose ones (Parmelia sulcata, Lobaria pulmonaria), whereas cortical CBSC did not change with distance from the road in any species. Strong positive correlations only occurred between the major medullary compound stictic acid present in L. pulmonaria and most heavy metals, consistent with a chelating role of stictic acid, but not of other studied CBSCs or in other species. However, heavy metal chelating did not protect L. pulmonaria against damage because this species experienced the strongest reduction in viability in the polluted sites. CBSCs with an accumulation potential for heavy metals should be quantified in lichen biomonitoring studies of heavy metals because they, like stictic acid, could overshadow pollutant inputs in some species rendering biomonitoring data less useful. In the two fruticose lichen species, CBSCs decreased with increasing heavy metal concentration, probably because heavy metal exposure impaired secondary metabolism. Thus, we found no support for a heavy metal protection role of any CBSCs in studied epiphytic lichens. No intraspecific relationships occurred between CBSCs versus N or C/N-ratio. Interspecifically, medullary CBSCs decreased and cortical CBSCs increased with increasing C/N-ratio. Copyright © 2015 Elsevier B.V. All rights reserved.

Dissolution and clearance of titanium tritide particles in the lungs of F344/Crl rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Yung-Sung; Snipes, M.B.; Wang, Yansheng

1995-12-01

Metal tritides are compounds in which the radioactive isotope tritium, following adsorption onto the metal, forms a stable chemical compound with the metal. When particles of tritiated metals become airborne, they can be inhaled by workers. Because the particles may be retained in the lung for extended periods, the resulting dose will be greater than doses following exposure to tritium gas or tritium oxide (HTO). Particles of triated metals may be dispersed into the air during routine handling, disruption of contaminated metals, or as a result of spontaneous radioactive decay processes. Unlike metal hydrides and deuterides, tritides are radioactive, andmore » the decay of the tritium atoms affects the metal. Because helium is a product of the decay, helium bubbles form within the metal tritide matrix. The pressure from these bubbles leads to respirable particles breaking off from the tritide surface. Our results show that a substantial amount of titanium tritide remains in the rat lung 10 d after intratracheal instillation, confirming results previously obtain in an in vitro dissolution study.« less

Compositions containing borane or carborane cage compounds and related applications

DOEpatents

Bowen, III, Daniel E; Eastwood, Eric A

2013-05-28

Compositions comprising a polymer-containing matrix and a filler comprising a cage compound selected from borane cage compounds, carborane cage compounds, metal complexes thereof, residues thereof, mixtures thereof, and/or agglomerations thereof, where the cage compound is not covalently bound to the matrix polymer. Methods of making and applications for using such compositions are also disclosed.

Compositions containing borane or carborane cage compounds and related applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowen, III, Daniel E; Eastwood, Eric A

2014-11-11

Compositions comprising a polymer-containing matrix and a filler comprising a cage compound selected from borane cage compounds, carborane cage compounds, metal complexes thereof, residues thereof, mixtures thereof, and/or agglomerations thereof, where the cage compound is not covalently bound to the matrix polymer. Methods of making and applications for using such compositions are also disclosed.

Compositions containing borane or carborane cage compounds and related applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowen, III, Daniel E.; Eastwood, Eric A.

2015-09-15

Compositions comprising a polymer-containing matrix and a filler comprising a cage compound selected from borane cage compounds, carborane cage compounds, metal complexes thereof, residues thereof, mixtures thereof, and/or agglomerations thereof, where the cage compound is not covalently bound to the matrix polymer. Methods of making and applications for using such compositions are also disclosed.

Antarctic snow: metals bound to high molecular weight dissolved organic matter.

PubMed

Calace, Nicoletta; Nardi, Elisa; Pietroletti, Marco; Bartolucci, Eugenia; Pietrantonio, Massimiliana; Cremisini, Carlo

2017-05-01

In this paper we studied some heavy metals (Cu, Zn, Cd, Pb, As, U) probably associated to high molecular weight organic compounds present in the Antarctic snow. Snow-pit samples were collected and analysed for high molecular weight fraction and heavy metals bound to them by means of ultrafiltration treatment. High molecular weight dissolved organic matter (HMW-DOM) recovered by ultrafiltration showed a dissolved organic carbon concentration (HMW-DOC) of about 18-83% of the total dissolved organic carbon measured in Antarctic snow. The characterisation of HMW-DOM fraction evidenced an ageing of organic compounds going from surface layers to the deepest ones with a shift from aliphatic compounds and proteins/amino sugars to more high unsaturated character and less nitrogen content. The heavy metals associated to HMW-DOM fraction follows the order: Zn > Cu > Pb > Cd ∼ As ∼ U. The percentage fraction of metals bound to HMW-DOM respect to total metal content follows the order: Cu > Pb > Zn, Cd in agreement with humic substance binding ability (Irwing-William series). Going down to depth of trench, all metals except arsenic, showed a high concentration peak corresponding to 2.0-2.5 m layer. This result was attributed to particular structural characteristic of organic matter able to form different type of complexes (1:1, 1:2, 1:n) with metals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Molecular and physiological mechanisms of plant tolerance to toxic metals

USDA-ARS?s Scientific Manuscript database

Plants have evolved a myriad of adaptive mechanisms based on a number of genes to deal with the different toxic metals they encounter in the soils worldwide. These genes encode a range of different metal and organic compound transporters and enzyme pathways for the synthesis of metal detoxifying lig...

ONR Far East Scientific Bulletin, Volume 7, Number 4, October-December 1982,

DTIC Science & Technology

1982-12-01

transition metal compounds (2), - ESR and relaxation (3), - rare earth and actinides (3), - magnetics and superconductivity (3), - transition metal...34Itinerant Electron Magnetism ," by T. Moriya, - "Organic Superconductivity ," by D. Jerome, and - "Recent Developments in Solid Earth Sciences," by...compounds, low dimension systems, random systems, surface magnetism , magnetism and superconductivity , Kondo problem, diamagnetism and nuclear

Hierarchical structures of metal micro- and nanoparticles for PIM

NASA Astrophysics Data System (ADS)

Pervikov, Aleksandr; Rodkevich, Nikolay; Glazkova, Elena; Lerner, Marat

2017-12-01

The design of the metal nanopowder composition to prepare the feedstock for powder injection molding was researched. The treatment of aluminum nanopowders with organic compounds was studied. The organic compounds sorbed on the surface of the nanoparticles was shown to change drastically the physico-mechanical characteristics of the nanopowders. These nanopowders demonstrate enhanced characteristics, in particularly, low reactivity, high compatibility with organic binder for feedstocks.

Synthesis of 4-substituted-trans-1,2-diaminocyclohexyl polyaminocarboxylate metal chelating agents for the preparation of stable radiometal antibody immunoconjugates for therapy and spect and pet imaging

DOEpatents

Mease, Ronnie C.; Kolsky, Kathryn L.; Mausner, Leonard F.; Srivastava, Suresh C.

1997-06-03

Cyclohexyl chelating agents useful in forming antibody-metal conjugates useful for diagnostic and therapeutic purposes. New compounds and processes of forming these compounds are disclosed including 4-haloacetamido-trans-1,2-diaminocyclohexyl polyaminocarboxylate and 4-isothiocyanato-trans-1,2-diamino cyclohexane-N, N, N', N'-tetra acetic acid.

Spin-Polarized Tunneling at Interfaces Between Oxides and Metals or Semiconductors

DTIC Science & Technology

2006-09-01

solution 3 3. Several miscellaneous compounds , including molecular oxygen and organic biradicals 4. Metals When a variable magnetic field is...substrate layer) Heusler alloys are considered to be prime candidates, because they show great potential for spin-injection contacts to compound and...usually employ simple parabolic bands and/or momentum and energy independent tunneling matrix elements. The classical theory of tunneling assumes that the

Separation and Identification of a Mixture of Group 6 Transition-Metal Carbonyl Compounds Using GC-MS in the General Chemistry Curriculum

ERIC Educational Resources Information Center

Fong, Lawrence K.

2004-01-01

Students in the general chemistry course are advised to scrutinize data obtained by gas chromatograph (GC) for segregation, and mass spectroscopy (MS) for recognizing combination of group 6 transition-metal carbonyl compounds. The GC-MS method arouses students' interest, as it can be applied to real-world situations, such as the routine…

Synthesis of 4-substituted-trans-1, 2-diaminocyclohexyl polyaminocarboxylate metal chelating agents for the preparation of stable radiometal antibody immunoconjugates for therapy and spect and pet imaging

DOEpatents

Mease, Ronnie C.; Mausner, Leonard F.; Srivastava, Suresh C.

1994-01-01

Cyclo agents useful in forming antibody-metal conjugates useful for diagnostic and therapeutic purposes. New compounds and processes of forming these compounds are disclosed including 4-haloacetamido-trans-1,2-diaminocyclohexyl polyaminocarboxylate and 4-isothiocyanato-trans-1,2-diamino cyclohexane-N,N,N',N'-tetra acetic acid.

X-ray Absorption Spectroscopy Systematics at the Tungsten L-Edge

PubMed Central

2015-01-01

A series of mononuclear six-coordinate tungsten compounds spanning formal oxidation states from 0 to +VI, largely in a ligand environment of inert chloride and/or phosphine, was interrogated by tungsten L-edge X-ray absorption spectroscopy. The L-edge spectra of this compound set, comprised of [W0(PMe3)6], [WIICl2(PMePh2)4], [WIIICl2(dppe)2][PF6] (dppe = 1,2-bis(diphenylphosphino)ethane), [WIVCl4(PMePh2)2], [WV(NPh)Cl3(PMe3)2], and [WVICl6], correlate with formal oxidation state and have usefulness as references for the interpretation of the L-edge spectra of tungsten compounds with redox-active ligands and ambiguous electronic structure descriptions. The utility of these spectra arises from the combined correlation of the estimated branching ratio of the L3,2-edges and the L1 rising-edge energy with metal Zeff, thereby permitting an assessment of effective metal oxidation state. An application of these reference spectra is illustrated by their use as backdrop for the L-edge X-ray absorption spectra of [WIV(mdt)2(CO)2] and [WIV(mdt)2(CN)2]2– (mdt2– = 1,2-dimethylethene-1,2-dithiolate), which shows that both compounds are effectively WIV species even though the mdt ligands exist at different redox levels in the two compounds. Use of metal L-edge XAS to assess a compound of uncertain formulation requires: (1) Placement of that data within the context of spectra offered by unambiguous calibrant compounds, preferably with the same coordination number and similar metal ligand distances. Such spectra assist in defining upper and/or lower limits for metal Zeff in the species of interest. (2) Evaluation of that data in conjunction with information from other physical methods, especially ligand K-edge XAS. (3) Increased care in interpretation if strong π-acceptor ligands, particularly CO, or π-donor ligands are present. The electron-withdrawing/donating nature of these ligand types, combined with relatively short metal–ligand distances, exaggerate the difference between formal oxidation state and metal Zeff or, as in the case of [WIV(mdt)2(CO)2], exert the subtle effect of modulating the redox level of other ligands in the coordination sphere. PMID:25068843

Studies of high temperature ternary phases in mixed-metal-rich early transition metal sulfide and phosphide systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marking, Gregory Allen

1994-01-04

Investigations of ternary mixed early transition metal-rich sulfide and phosphide systems resulted in the discovery of new structures and new phases. A new series of Zr and Hf - group V transition metal - sulfur K-phases was synthesized and crystallographically characterized. When the group V transition metal was Nb or Ta, the unit cell volume was larger than any previously reported K-phase. The presence of adventitious oxygen was determined in two K-phases through a combination of neutron scattering and X-ray diffraction experiments. A compound Hf 10Ta 3S 3 was found to crystallize in a new-structure type similar to the knownmore » gamma brasses. This structure is unique in that it is the only reported "stuffed" gamma-brass type structure. The metal components, Hf and Ta, are larger in size and more electropositive than the metals found in normal gamma brasses (e.g. Cu and Zn) and because of the larger metallic radii, sulfur can be incorporated into the structure where it plays an integral role in stabilizing this phase relative to others. X-ray single-crystal, X-ray powder and neutron powder refinements were performed on this structure. A new structure was found in the ternary Nb-Zr-P system which has characteristics in common with many known early transition metal-rich sulfides, selenides, and phosphides. This structure has the simplest known interconnection of the basic building blocks known for this structural class. Anomalous scattering was a powerful tool for differentiating between Zr and Nb when using Mo Kα X-radiation. The compounds ZrNbP and HfNbP formed in the space group Prima with the simple Co 2Si structure which is among the most common structures found for crystalline solid materials. Solid solution compounds in the Ta-Nb-P, Ta-Zr-P, Nb-Zr-P, Hf-Nb-P, and Hf-Zr-S systems were crystallographically characterized. The structural information corroborated ideas about bonding in metal-rich compounds.« less

An Alternative Approach to the Teaching of Systematic Transition Metal Chemistry.

ERIC Educational Resources Information Center

Hathaway, Brian

1979-01-01

Presents an alternative approach to teaching Systematic Transition Metal Chemistry with the transition metal chemistry skeleton features of interest. The "skeleton" is intended as a guide to predicting the chemistry of a selected compound. (Author/SA)

Metallic behavior and periodical valence ordering in a MMX chain compound, Pt(2)(EtCS(2))(4)I.

PubMed

Mitsumi, M; Murase, T; Kishida, H; Yoshinari, T; Ozawa, Y; Toriumi, K; Sonoyama, T; Kitagawa, H; Mitani, T

2001-11-14

A new one-dimensional (1-D) halogen-bridged mixed-valence diplatinum(II,III) compound, Pt(2)(EtCS(2))(4)I (3), has been successfully synthesized from [Pt(2)(EtCS(2))(4)] (1) and [Pt(2)(EtCS(2))(4)I(2)] (2). These three compounds have been examined using UV-visible-near-IR, IR, polarized Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray crystal structure analyses (except for 1). Compound 3 was further characterized through electrical transport measurements, determination of the temperature dependence of lattice parameters, X-ray diffuse scattering, and SQUID magnetometry. 3 crystallizes in the monoclinic space group C2/c and exhibits a crystal structure consisting of neutral 1-D chains with a repeating -Pt-Pt-I- unit lying on the crystallographic 2-fold axis parallel to the b axis. The Pt-Pt distance at 293 K is 2.684 (1) A in the dinuclear unit, while the Pt-I distances are essentially equal (2.982 (1) and 2.978 (1) A). 3 shows relatively high electrical conductivity (5-30 S cm(-1)) at room temperature and undergoes a metal-semiconductor transition at T(M-S) = 205 K. The XPS spectrum in the metallic state reveals a Pt(2+) and Pt(3+) mixed-valence state on the time scale of XPS spectroscopy ( approximately 10(-17) s). In accordance with the metal-semiconductor transition, anomalies are observed in the temperature dependence of the crystal structure, lattice parameters, X-ray diffuse scattering, and polarized Raman spectra near T(M-S). In variable-temperature crystal structure analyses, a sudden and drastic increase in the Pt-I distance near the transition temperature is observed. Furthermore, a steep increase in U(22) of iodine atoms in the 1-D chain direction has been observed. The lattice parameters exhibit significant temperature dependence with drastic change in slope at about 205-240 K. This was especially evident in the unit cell parameter b (1-D chain direction) as it was found to lengthen rapidly with increasing temperature. X-ray diffraction photographs taken utilizing the fixed-film and fixed-crystal method for the metallic state revealed the presence of diffuse scattering with line shapes parallel to the a* axis indexed as (-, n + 0.5, l) (n; integer). Diffuse scattering with k = n + 0.5 is considered to originate from the 2-fold periodical ordering corresponding to -Pt(2+)-Pt(2+)-I-Pt(3+)-Pt(3+)-I- or -Pt(2+)-Pt(3+)-I-Pt(3+)-Pt(2+)-I- in an extremely short time scale. Diffuse lines corresponding to 2-D ordering progressively decrease in intensity below 252 K and are converted to the diffuse planes corresponding to 1-D ordering near T(M-S). Furthermore, diffuse planes condensed into superlattice reflections below T(M-S). Polarized Raman spectra show temperature dependence through a drastic low-energy shift of the Pt-I stretching mode and also through broadening of bands above T(M-S).

Diazo compounds and N-tosylhydrazones: novel cross-coupling partners in transition-metal-catalyzed reactions.

PubMed

Xiao, Qing; Zhang, Yan; Wang, Jianbo

2013-02-19

Transition-metal-catalyzed carbene transformations and cross-couplings represent two major reaction types in organometallic chemistry and organic synthesis. However, for a long period of time, these two important areas have evolved separately, with essentially no overlap or integration. Thus, an intriguing question has emerged: can cross-coupling and metal carbene transformations be merged into a single reaction cycle? Such a combination could facilitate the development of novel carbon-carbon bond-forming methodologies. Although this concept was first explored about 10 years ago, rapid developments inthis area have been achieved recently. Palladium catalysts can be used to couple diazo compounds with a wide variety of organic halides. Under oxidative coupling conditions, diazo compounds can also react with arylboronic acids and terminal alkynes. Both of these coupling reactions form carbon-carbon double bonds. As the key step in these catalytic processes, Pd carbene migratory insertion plays a vital role in merging the elementary steps of Pd intermediates, leading to novel carbon-carbon bond formations. Because the diazo substrates can be generated in situ from N-tosylhydrazones in the presence of base, the N-tosylhydrazones can be used as reaction partners, making this type of cross-coupling reaction practical in organic synthesis. N-Tosylhydrazones are easily derived from the corresponding aldehydes or ketones. The Pd-catalyzed cross-coupling of N-tosylhydrazones is considered a complementary reaction to the classic Shapiro reaction for converting carbonyl functionalities into carbon-carbon double bonds. It can also serve as an alternative approach for the Pd-catalyzed cross-coupling of carbonyl compounds, which is usually achieved via triflates. The combination of carbene formation and cross-coupling in a single catalytic cycle is not limited to Pd-catalyzed reactions. Recent studies of Cu-, Rh-, Ni-, and Co-catalyzed cross-coupling reactions with diazo compounds or N-tosylhydrazones show that these transformations also work with other transition metals, demonstrating the generality of the diazo compounds as new cross-coupling partners in transition-metal-catalyzed coupling reactions.

Maximum-valence radii of transition metals

PubMed Central

Pauling, Linus

1975-01-01

In many of their compounds the transition metals have covalence 9, forming nine bonds with use of nine hybrid spd bond orbitals. A set of maximum-valence single-bond radii is formulated for use in these compounds. These radii are in reasonably good agreement with observed bond lengths. Quadruple bonds between two transition metal atoms are about 50 pm (iron-group atoms) or 55 pm (palladium and platinum-group atoms) shorter than single bonds. This amount of shortening corresponds to four bent single bonds with the best set of bond angles, 79.24° and 128.8°. PMID:16578730

Oxide films state analysis by IR spectroscopy based on the simple oscillator approximation

NASA Astrophysics Data System (ADS)

Volkov, N. V.; Yakutkina, T. V.; Karpova, V. V.

2017-05-01

Stabilization of structure-phase state in a wide temperature range is one of the most important problems of improving properties of oxide compounds. As such, the search of new effective methods for obtaining metal oxides with desired physic-chemical, electro-physical and thermal properties and their control is important and relevant. The aim of this work is identification features state of the oxide films of some metals Be, Al, Fe, Cu, Zr on the metal surface of the polycrystalline samples by infrared spectroscopy. To identify the resonance emission bands the algorithm of IR-spectra processing was developed and realized on the basis of table processor EXCEL-2010, which allow revealing characteristic resonance bands successfully and identification of inorganic chemical compounds. In the frame of simple oscillator model, resonance frequencies of normal vibrations of water and some inorganic compounds: metal oxides - Be, Al, Fe, Cu, Zr were calculated and characteristic frequencies for different states (aggregate, deformation, phase) were specified. By means of IR-spectroscopy fundamental possibility of revealing oxides films on metal substrate features state is shown, that allow development and optimization of the technology for production of the oxide films with desired properties.

Binding in alkali and alkaline-earth tetrahydroborates: Special position of magnesium tetrahydroborate

NASA Astrophysics Data System (ADS)

Łodziana, Zbigniew; van Setten, Michiel J.

2010-01-01

Compounds of light elements and hydrogen are currently extensively studied due to their potential application in the field of hydrogen or energy storage. A number of new interesting tetrahydroborates that are especially promising due to their very high gravimetric hydrogen content were recently reported. However, the determination and understanding of their complex crystalline structures has created considerable debate. Metal tetrahydroborates, in general, form a large variety of structures ranging from simple for NaBH4 to very complex for Mg(BH4)2 . Despite the extensive discussion in the literature no clear explanation has been offered for this variety so far. In this paper we analyze the structural and electronic properties of a broad range of metal tetrahydroborates and reveal the factors that determine their structure: ionic bonding, the orientation of the BH4 groups, and the coordination number of the metal cation. We show, in a simple way, that the charge transfer in the metal tetrahydroborates rationally explains the structural diversity of these compounds. Being ionic systems, the metal tetrahydroborates fall into the classification of Linus Pauling. By using the ionic radius for the BH4 group as determined in this paper, this allows for structural predictions for new and mixed compounds.

Tridentate ligated heteronuclear tin(II) alkoxides for use as base catalysts

DOEpatents

Boyle, Timothy J.

2001-01-01

Tin alkoxide compounds are provided with accessible electrons. The tin alkoxide compound have the general formula (THME).sub.2 Sn.sub.3 (M(L).sub.x).sub.y, where THME is (O--CH.sub.2).sub.3 C(CH.sub.3), M is a metal atom selected from Sn and Ti, L is an organic/inorganic ligand selected from an alkoxide, a phenoxide or an amide, x is selected from 2 and 4 and y is selected from 0 and 1. These compounds have applicability as base catalysts in reactions and in metal-organic chemical vapor depositions processes.

Fischer-Tropsch process

DOEpatents

Dyer, Paul N.; Pierantozzi, Ronald; Withers, Howard P.

1987-01-01

A Fischer-Tropsch process utilizing a product selective and stable catalyst by which synthesis gas, particularly carbon-monoxide rich synthesis gas is selectively converted to higher hydrocarbons of relatively narrow carbon number range is disclosed. In general, the selective and notably stable catalyst, consist of an inert carrier first treated with a Group IV B metal compound (such as zirconium or titanium), preferably an alkoxide compound, and subsequently treated with an organic compound of a Fischer-Tropsch metal catalyst, such as cobalt, iron or ruthenium carbonyl. Reactions with air and water and calcination are specifically avoided in the catalyst preparation procedure.

Synthesis, structural and fungicidal studies of hydrazone based coordination compounds

NASA Astrophysics Data System (ADS)

Sharma, Amit Kumar; Chandra, Sulekh

2013-02-01

The coordination compounds of the Co(II), Ni(II) and Cu(II) metal ions derived from imine based ligand, benzil bis(carbohydarzone) were structurally and pharmaceutically studied. The compounds have the general stoichiometry [M(L)]X2 and [Co(L)X2], where M = Ni(II) and Cu(II), and X=NO3- and Cl- ions. The analytical techniques like elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, UV/Visible, NMR, ESI mass and EPR were used to study the compounds. The key IR bands, i.e., amide I, amide II and amide III stretching vibrations accounts for the tetradentate metal binding nature of the ligand. The electronic and EPR spectral results suggest the square planar Ni(II) and Cu(II) complexes (giso = 2.11-2.22) and tetragonal geometry Co(II) complexes (giso = 2.10-2.17). To explore the compounds in the biological field, they were examined against the opportunistic pathogens, i.e., Alternaria brassicae, Aspergillus niger and Fusarium oxysporum. The partial covalent character of metal-ligand bond is supported by the orbital reduction factor k (0.62-0.92) and nephalauxetic parameter β (0.55-0.57).

New hydrogen-rich ammonium metal borohydrides, NH4[M(BH4)4], M = Y, Sc, Al, as potential H2 sources.

PubMed

Starobrat, A; Jaroń, T; Grochala, W

2018-03-26

Three metal-ammonium borohydrides, NH4[M(BH4)4] M = Y, Sc, Al, denoted 1, 2, 3, respectively, were prepared via a low temperature mechanochemical synthesis and characterized using PXRD, FTIR and TGA/DSC/MS. The compounds 1 and 2 adopt the P21/c space group while the compound 3 crystallizes in an orthorhombic unit cell (Fddd). The first decomposition step of all three derivatives of ammonium borohydride has the maximum rate at 48 °C, 53 °C and 35 °C for 1, 2 and 3, respectively, which are comparable to that for NH4BH4 (53 °C). The thermal decomposition of these metal-ammonium borohydrides is a multistep process, with predominantly exothermic low-temperature stages. The compound 1 decomposes via known Y(BH4)3, however, some of the solid decomposition products of the other two compounds have not been fully identified. In the system containing compound 2, a new, more dense polymorph of the previously reported LiSc(BH4)4 has been detected as the intermediate of slow decomposition at room temperature.

Application of the exact exchange potential method for half metallic intermediate band alloy semiconductor.

PubMed

Fernández, J J; Tablero, C; Wahnón, P

2004-06-08

In this paper we present an analysis of the convergence of the band structure properties, particularly the influence on the modification of the bandgap and bandwidth values in half metallic compounds by the use of the exact exchange formalism. This formalism for general solids has been implemented using a localized basis set of numerical functions to represent the exchange density. The implementation has been carried out using a code which uses a linear combination of confined numerical pseudoatomic functions to represent the Kohn-Sham orbitals. The application of this exact exchange scheme to a half-metallic semiconductor compound, in particular to Ga(4)P(3)Ti, a promising material in the field of high efficiency solar cells, confirms the existence of the isolated intermediate band in this compound. (c) 2004 American Institute of Physics.

Contaminant Removal From Natural Resources

NASA Technical Reports Server (NTRS)

Clausen, Christian A. (Inventor); Quinn, Jacqueline W. (Inventor); Geiger, Cheri L. (Inventor); Reinhart, Debra (Inventor); Fillpek, Laura B. (Inventor); Coon, Christina (Inventor); Devor, Robert (Inventor)

2006-01-01

A zero-valent metal emulsion containing zero-valent metal particles is used to remediate contaminated natural resources, such as groundwater and soil. In a preferred embodiment, the zero-valent metal emulsion removes heavy metals, such as lead (pb), from contaminated natural resources. In another preferred embodiment, the zero-valent metal emulsion is a bimetallic emulsion containing zero-valent metal particles doped with a catalytic metal to remediate halogenated aromatic compounds, such as polychlorinated biphenyls (PCBs), from natural resources.

Investigation of magnetic properties in the case of three families of 1-dimensional magnets: M(II)A(4,4'-bipyridine); M = iron, cobalt, nickel, copper; A = chloride, nitrogen, (ox)

NASA Astrophysics Data System (ADS)

Danilovic, Dusan S.

Magnetic properties of three families of metal-organic coordinated networks which have the general form of M(II)A(4,4'-bipyridine), where M=Fe, Ni, Co, and Cu and A=Cl2, (ox) and (N3)2, are studied in this dissertation. Novel Ni(N3)2(4,4'-bipyridine), Co(N3)2(4,4'-bipyridine) and Cu(N 3)2(4,4'-bipyridine) have been synthesized. We applied different synthesis procedures and produced Ni, Co, and Cu azide compounds for the first time, thus leaving the hydrothermal route procedure. Powder x-ray diffraction at room temperature was done in order to establish the crystal structure of the members of these three families. It was found that all of them crystallize in orthorhombic structure, where transitional metals have an octahedral coordination. Since all three families have identical crystal structure we got opportunity to examine how ligands facilitate magnetic interaction between metallic centers and also to test existing magnetic theoretical models. Since 4,4'-bipyridine is much longer than other ligands, our systems can be considered as 1-D magnetic systems. Their interchain magnetic interactions are very weak, and they order magnetically at very low temperatures of the order of few K. Measurements of M(H) at temperatures T=1.9K and T=2K and chi(T) in different external magnetic fields in zero field and field cooled modes have been made. In the case of MCl2(4,4'-bipyridine) family of compounds, we observed ferromagnetic interactions between metal ions within the chains and antiferromagnetic interactions between adjacent chains. M(ox)(4,4'-bipyridine) family of metal-organic compounds has antiferromagnetic interactions between the transitional metal ions within the chain, while weak ferromagnetic interaction exists between the chains. All members in the M(N3)2(4,4'-bipyridine) family except in the case of the copper compound were found to have ferromagnetic interactions between metal ions within the chains and then antiferromagnetic interactions between adjacent chains. The copper compound does not show magnetic ordering in the temperature range we considered. All the metal ions in these compounds were detected in high spin states. The magnetic susceptibility data was fit to appropriate 1-D models, which in the case of MCl2(4,4'-bipyridine) and M(N3)2(4,4'-bipyridine) were the Classical Spin Fisher model, and the Bonner Fisher model in the case M(ox)(4,4'-bipyridine). The experimental results and fitting to the appropriate model with the accuracy of 0.995 suggests that shorter Cl-M-Cl distances facilitate ferromagnetic interactions, which are more sensitive to the total spin value then to the sole distance between metal ions. The magnetic behavior of M(N3) 2(4,4'-bipyridine) family of coordinated metal-organic compounds is very interesting because family members exhibit both ferromagnetic and antiferromagnetic behavior. The ferromagnetic characteristics decrease with decreasing spin. Fitting the results for all compounds of the M(ox)(4,4'-bipyridine) family have shown that strong anisotropy exists in all of them, being highest in Ni(ox)(4,'4-bipyridine) and lowest in Co(ox)(4,4'-bipyridine). Specific heat measurements were performed in the case of cobalt and copper azide compounds and then compared with previously obtained results for the iron coordinated network of the same family. Although none of these compounds show the characteristic lambda shaped transition indicating magnetic ordering, all of them have unusually large values of the constant gamma, which indicates significant magnetic contribution to the observed specific heat, since the free electron contribution in these observed families is negligible. We have concluded that total spin of the transitional metal plays a more important role than the distance between ions within the chain in determining magnitude of interaction, and that (N3)2 is a better facilitator of ferromagnetic interaction between ions than Cl2.

Presence of novel compound BCR-ABL mutations in late chronic and advanced phase imatinib sensitive CML patients indicates their possible role in CML progression.

PubMed

Akram, Afia Muhammad; Iqbal, Zafar; Akhtar, Tanveer; Khalid, Ahmed Mukhtar; Sabar, Muhammad Farooq; Qazi, Mahmood Hussain; Aziz, Zeba; Sajid, Nadia; Aleem, Aamer; Rasool, Mahmood; Asif, Muhammad; Aloraibi, Saleh; Aljamaan, Khaled; Iqbal, Mudassar

2017-04-03

BCR-ABL kinase domain (K D ) mutations are well known for causing resistance against tyrosine kinase inhibitors (TKIs) and disease progression in chronic myeloid leukemia (CML). In recent years, compound BCR-ABL mutations have emerged as a new threat to CML patients by causing higher degrees of resistance involving multiple TKIs, including ponatinib. However, there are limited reports about association of compound BCR-ABL mutations with disease progression in imatinib (IM) sensitive CML patients. Therefore, we investigated presence of ABL-K D mutations in chronic phase (n = 41), late chronic phase (n = 33) and accelerated phase (n = 16) imatinib responders. Direct sequencing analysis was used for this purpose. Eleven patients (12.22%) in late-CP CML were detected having total 24 types of point mutations, out of which 8 (72.72%) harbored compound mutated sites. SH2 contact site mutations were dominant in our study cohort, with E355G (3.33%) being the most prevalent. Five patients (45%) all having compound mutated sites, progressed to advanced phases of disease during follow up studies. Two novel silent mutations G208G and E292E/E were detected in combination with other mutants, indicating limited tolerance for BCR-ABL1 kinase domain for missense mutations. However, no patient in early CP of disease manifested mutated ABL-K D . Occurrence of mutations was found associated with elevated platelet count (p = 0.037) and patients of male sex (p = 0.049). The median overall survival and event free survival of CML patients (n = 90) was 6.98 and 5.8 y respectively. The compound missense mutations in BCR-ABL kinase domain responsible to elicit disease progression, drug resistance or disease relapse in CML, can be present in yet Imatinib sensitive patients. Disease progression observed here, emphasizes the need of ABL-K D mutation screening in late chronic phase CML patients for improved clinical management of disease.

DEMONSTRATION BULLETIN: METAL-ENHANCED ABIOTIC DEGRADATION TECHNOLOGY - ENVIROMETAL TECHNOLOGIES, INC.

EPA Science Inventory

EnviroMetal Technologies, Inc. (ETI), of Guelph, ON, Canada, has developed the metal-enhanced abiotic degradation technology to treat halogenated volatile organic compounds (VOC) in water. A reactive, zero-valent, granular iron medium causes reductive dehalogenation of VOCs yield...

Nanoscale perspective: Materials designs and understandings in lithium metal anodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Dingchang; Liu, Yayuan; Pei, Allen

Li metal chemistry is a promising alternative with a much higher energy density than that of state-of-the-art Li-ion counterparts. However, significant challenges including safety issues and poor cyclability have severely impeded Li metal technology from becoming viable. In recent years, nanotechnologies have become increasingly important in materials design and fabrication for Li metal anodes, contributing to major progress in the field. In this review, we first introduce the main achievements in Li metal battery systems fulfilled by nanotechnologies, particularly regarding Li metal anode design and protection, ultrastrong separator engineering, safety monitoring, and smart functions. Next, we introduce recent studies onmore » nanoscale Li nucleation/deposition. Lastly, we discuss possible future research directions. We hope this review delivers an overall picture of the role of nanoscale approaches in the recent progress of Li metal battery technology and inspires more research in the future.« less

Nanoscale perspective: Materials designs and understandings in lithium metal anodes

DOE PAGES

Lin, Dingchang; Liu, Yayuan; Pei, Allen; ...

2017-05-19

Li metal chemistry is a promising alternative with a much higher energy density than that of state-of-the-art Li-ion counterparts. However, significant challenges including safety issues and poor cyclability have severely impeded Li metal technology from becoming viable. In recent years, nanotechnologies have become increasingly important in materials design and fabrication for Li metal anodes, contributing to major progress in the field. In this review, we first introduce the main achievements in Li metal battery systems fulfilled by nanotechnologies, particularly regarding Li metal anode design and protection, ultrastrong separator engineering, safety monitoring, and smart functions. Next, we introduce recent studies onmore » nanoscale Li nucleation/deposition. Lastly, we discuss possible future research directions. We hope this review delivers an overall picture of the role of nanoscale approaches in the recent progress of Li metal battery technology and inspires more research in the future.« less

Metal cleaner poisoning

MedlinePlus

Metal cleaners contain organic compounds called hydrocarbons, including: 1,2-butylene oxide Boric acid Cocoyl sarcosine Dicarboxylic fatty acid Dimethoxymethane Dodecanedioic acid N-propyl bromide Sodium hydroxide T-butanol

Structure of transition-metal cluster compounds: Use of an additional orbital resulting from the f, g character of spd bond orbitals*

PubMed Central

Pauling, Linus

1977-01-01

A general theory of the structure of complexes of the transition metals is developed on the basis of the enneacovalence of the metals and the requirements of the electroneutrality principle. An extra orbital may be provided through the small but not negligible amount of f and g character of spd bond orbitals, and an extra electron or electron pair may be accepted in this orbital for a single metal or a cluster to neutralize the positive electric charge resulting from the partial ionic character of the bonds with ligands, such as the carbonyl group. Examples of cluster compounds of cobalt, ruthenium, rhodium, osmium, and gold are discussed. PMID:16592470

Structure of transition-metal cluster compounds: Use of an additional orbital resulting from the f, g character of spd bond orbitals.

PubMed

Pauling, L

1977-12-01

A general theory of the structure of complexes of the transition metals is developed on the basis of the enneacovalence of the metals and the requirements of the electroneutrality principle. An extra orbital may be provided through the small but not negligible amount of f and g character of spd bond orbitals, and an extra electron or electron pair may be accepted in this orbital for a single metal or a cluster to neutralize the positive electric charge resulting from the partial ionic character of the bonds with ligands, such as the carbonyl group. Examples of cluster compounds of cobalt, ruthenium, rhodium, osmium, and gold are discussed.

Synthesis of a sugar-organometallic compound 1,1‧-difurfurylferrocene and its microwave preparation of carbon/iron oxide nanocomposite

NASA Astrophysics Data System (ADS)

Zhao, Shanyu; Cooper, Daniel C.; Xu, Haixun; Zhu, Pinghua; Suggs, J. William

2013-01-01

In order to synthesize a carbon-metal or metal oxide combination sphere, carbonaceous resource furfural 1 was introduced, which was nucleophilic treated with 1,1‧-dilithioferrocene 2 to form a sugar-organometallic compound: ferrocenyl monosaccharide derivative 1,1‧-difurfurylferrocene 3. 1,1‧-Difurfurylferrocene 3 can be hydrothermally treated in a microwave reactor to give 300-500 nm microspheres with the α-Fe2O3 or Fe3O4 nanocrystals formed on the surface, which may be favorable for new magnetic materials preparation or instead of iron with other metal ions, versatile carbon/metal composites will be possibly synthesized for catalysis, drug delivery and magnetic uses.

A rapid and rational approach to generating isomorphous heavy-atom phasing derivatives

PubMed Central

Lu, Jinghua; Sun, Peter D.

2014-01-01

In attempts to replace the conventional trial-and-error heavy-atom derivative search method with a rational approach, we previously defined heavy metal compound reactivity against peptide ligands. Here, we assembled a composite pH and buffer-dependent peptide reactivity profile for each heavy metal compound to guide rational heavy-atom derivative search. When knowledge of the best-reacting heavy-atom compound is combined with mass spectrometry-assisted derivatization, and with a quick-soak method to optimize phasing, it is likely that the traditional heavy-atom compounds could meet the demand of modern high-throughput X-ray crystallography. As an example, we applied this rational heavy-atom phasing approach to determine a previously unknown mouse serum amyloid A2 crystal structure. PMID:25040395

Solvent-free synthesis of new metal phosphites with double-layered, pillared-layered, and framework structures

NASA Astrophysics Data System (ADS)

Liu, Lin; Zhang, Wei; Shi, Zhonghua; Chen, Yaoqiang; Lin, Zhien

2014-12-01

Three new metal phosphites, formulated as (H3O)2·Mn2(HPO3)3 (1), Co(bpy) (H2O) (HPO3) (2), and H2tmpda·Zn3(HPO3)4 (3), have been synthesized under solvent-free conditions, where bpy = 4,4‧-bipyridine, and tmpda = N,N,N‧,N‧-tetramethyl-1,3-propanediamine. Compound 1 has a double-layered structure with a thickness of 5.68 Å. Compound 2 has an inorganic-organic hybrid framework with cobalt phosphite layers pillared by bpy ligands. Compound 3 has a three-dimensional open-framework structure containing 8-ring channels. The temperature dependence of the magnetic susceptibility of compounds 1 and 2 were also investigated.

Structural, electronic and magnetic properties of Cd1-xTMxS (TM=Co and V) by ab-initio calculations

NASA Astrophysics Data System (ADS)

Yahi, Hakima; Meddour, Athmane

2016-03-01

The structural, electronic and ferromagnetic properties of Cd1-xTMxS (TM=Co and V) compounds at x=0.25, 0.50 and 0.75 in zinc blende (B3) phase, have been investigated using all-electron full-potential linear muffin tin orbital (FP-LMTO) calculations within the frame work of the density functional theory and the generalized gradient approximation. The electronic properties exhibit half-metallic behavior at x=0.25, 0.50, and 0.75 for Cd1-xVxS and x=0.25 and 0.50 for Cd1-xCoxS, while Cd1-xCoxS with x=0.75 is nearly half-metallic. The calculated magnetic moment per substituted transition metal (TM) atom for half-metallic compounds is found to be 3 μB, whereas that of a nearly half-metallic compound is 2.29 μB. The analysis of band structure and density of states shows that the TM-3d states play a key role in generating spin-polarization and magnetic moment in these compounds. Furthermore, we establish that the p-d hybridization reduces the local magnetic moment of Co and enhances that of V from their free space charge value of 3 μB and creates small local magnetic moments on nonmagnetic Cd and S sites. The exchange constant N0α and N0β have been calculated to validate the effects resulting from exchange splitting process.

Design, spectral characterization and biological studies of transition metal(II) complexes with triazole Schiff bases

NASA Astrophysics Data System (ADS)

Hanif, Muhammad; Chohan, Zahid H.

2013-03-01

A new series of three biologically active triazole derived Schiff base ligands L1-L3 have been synthesized in equimolar reaction of 3-amino-1H-1,2,4-triazole with pyrrol-2-carboxaldehyde, 4-bromo-thiophene-2-carboxaldehyde, and 5-iodo-2-hydroxy benzaldehyde. The prepared Schiff bases were used for further complex formation reaction with different metal elements like Co(II), Ni(II), Cu(II) and Zn(II) as chlorides by using a molar ratio of ligand:metal as 2:1. The structure and bonding nature of all the compounds were identified by their physical, spectral and analytical data. All the metal(II) complexes possessed an octahedral geometry except the Cu(II) complexes which showed a distorted octahedral geometry. All the synthesized compounds, were studied for their in vitro antibacterial, and antifungal activities, against four Gram-negative (Escherichia coli, Shigella sonnei, Pseudomonas aeruginosa and Salmonella typhi) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains and against six fungal strains (Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glabrata) by using agar-well diffusion method. It has been shown that all the synthesized compounds showed moderate to significant antibacterial activity against one or more bacterial strains. In vitro Brine Shrimp bioassay was also carried out to investigate the cytotoxic properties of these compounds. The data also revealed that the metal complexes showed better activity than the ligands due to chelation/coordination.

Bimetallic catalysis involving dipalladium(I) and diruthenium(I) complexes.

PubMed

Das, Raj K; Saha, Biswajit; Rahaman, S M Wahidur; Bera, Jitendra K

2010-12-27

Dipalladium(I) and diruthenium(I) compounds bridged by two [{(5,7-dimethyl-1,8-naphthyridin-2-yl)amino}carbonyl]ferrocene (L) ligands have been synthesized. The X-ray structures of [Pd(2)L(2)][BF(4)](2) (1) and [Ru(2)L(2)(CO)(4)][BF(4)](2) (2) reveal dinuclear structures with short metal-metal distances. In both of these structures, naphthyridine bridges the dimetal unit, and the site trans to the metal-metal bond is occupied by weakly coordinating oxygen from the amido fragment. The catalytic utilities of these bimetallic compounds are evaluated. Compound 1 is an excellent catalyst for phosphine-free, Suzuki cross-coupling reactions of aryl bromides with arylboronic acids and provides high yields in short reaction times. Compound 1 is also found to be catalytically active for aryl chlorides, although the corresponding yields are lower. A bimetallic mechanism is proposed, which involves the oxidative addition of aryl bromide across the Pd-Pd bond and the bimetallic reductive elimination of the product. Compound 1 is also an efficient catalyst for the Heck cross-coupling of aryl bromides with styrenes. The mechanism for aldehyde olefination with ethyl diazoacetate (EDA) and PPh(3), catalyzed by 2, has been fully elucidated. It is demonstrated that 2 catalyzes the formation of phosphorane utilizing EDA and PPh(3), which subsequently reacts with aldehyde to produce a new olefin and phosphine oxide. The efficacy of bimetallic complexes in catalytic organic transformations is illustrated in this work.

Process for making transition metal nitride whiskers

DOEpatents

Bamberger, Carlos E.

1989-01-01

A process for making metal nitrides, particularly titanium nitride whiskers, using a cyanide salt as a reducing agent for a metal compound in the presence of an alkali metal oxide. Sodium cyanide, various titanates and titanium oxide mixed with sodium oxide react to provide titanium nitride whiskers that can be used as reinforcement to ceramic composites.

PRODUCTION OF METALS

DOEpatents

Spedding, F.H.; Wilhelm, H.A.; Keller, W.H.

1961-09-19

A process is described producing metallic thorium, titanium, zirconium, or hafnium from the fluoride. In the process, the fluoride is reduced with alkali or alkaline earth metal and a booster compound (e.g. iodine or a decomposable oxysalt) in a sealed bomb at superatmospheric pressure and a temperature above the melting point of the metal to be produced.

Hydrous oxide ion-exchange compound catalysts

DOEpatents

Dosch, Robert G.; Stephens, Howard P.

1990-01-01

A catalytic material of improved activity which comprises a hydrous, alkali metal or alkaline earth metal or quaternary ammonium titanate, zirconate, niobate, or tantalate, in which the metal or ammonium cations have been exchange with a catalytically effective quantity of a catalyst metal, and which has been subsequently treated with a solution of a Bronsted acid.

Bioassisted Phytomining of Gold

NASA Astrophysics Data System (ADS)

Maluckov, Biljana S.

2015-05-01

Bioassisted phytomining implies targeted use of microorganisms and plants for the selective recovery of the metal. Metals from undissolved compounds are dissolved by applying specially chosen microorganisms and therefore become available to the hyperaccumulating plants. In the article, the selective extraction method of base metals and the precious metal gold by using microorganisms and plants is discussed.

Mobility and bio-availability of heavy metals in anthropogenically contaminated alluvial (deluvial) meadow soils (EUTRIC FLUVISOLS)

NASA Astrophysics Data System (ADS)

Dinev, Nikolai; Hristova, Mariana; Tzolova, Venera

2015-04-01

The total content of heavy metals is not sufficient to assess the pollution and the risk for environment as it does not provide information for the type and solubility of heavy metals' compounds in soils. The purpose was to study and determine the mobility of heavy metals in anthropogenically contaminated alluvial (delluvial) meadow soils spread around the non-ferrous plant near the town of Asenovgrad in view of risk assessment for environment pollution. Soil samples from monitoring network (1x1 km) was used. The sequential extraction procedure described by Zein and Brummer (1989) was applied. Results showed that the easily mobilizable cadmium compounds predominate in both contaminated and not contaminated soils. The stable form of copper (associated with silicate minerals, carbonates or amorphous and crystalline oxide compounds) predominates only in non polluted soils and reviles the risk of the environment contamination. Lead spreads and accumulates as highly soluble (mobile) compounds and between 72.3 and 99.6 percent of the total lead is bioavailable in soils. The procedure is very suitable for studying the mobility of technogenic lead and copper in alluvial soils with neutral medium reaction and in particular at the high levels of cadmium contamination. In soils with alkaline reaction - polluted and unpolluted the error of analysis increases for all studied elements.

Mixed valence transition metal 2D-oxides: Comparison between delafossite and crednerite compounds

NASA Astrophysics Data System (ADS)

Martin, Christine; Poienar, Maria

2017-08-01

Transition metal oxides offer large opportunities to study relationships between structures and properties. Indeed these compounds crystallize in numerous frameworks corresponding to different dimensionalities and, accordingly, show a huge variety of properties (as high Tc superconductivity, colossal magnetoresistivity, multiferroicity..). The control of the oxidation state of the transition metal, via the monitoring of the oxygen content, is of prime importance to understand and optimize the properties, due to the strong coupling that exists between the lattice and the charges and spins of the transition metals. In this large playground for chemists, we reinvestigated several 2D-compounds derived from delafossite structure. Considering this paper as a very short review, we report here the results obtained on CuMO2 compounds (with M = Cr, Mn or Mn+Cu) by using a combination of techniques, as X-ray, neutrons and/or electrons diffraction on poly-crystals for structural characterisations that are correlated with electrical and/or magnetic properties. The complementarity of studies is also addressed by the synthesis and characterization of single crystals in addition to poly-crystals. Moreover the comparison of the structures of similar Cr and Mn based oxides highlights the crucial role of the Jahn-Teller effect of trivalent manganese to lift the degeneracy, which is responsible of the magnetic frustration in CuCrO2.

Glass corrosion in natural environments

NASA Technical Reports Server (NTRS)

Thorpe, Arthur N.; Barkatt, Aaron

1992-01-01

Experiments carried out during the progress period are summarized. Experiments carried out involving glass samples exposed to solutions of Tris have shown the appearance of 'spikes' upon monitoring glass dissolution as a function of time. The periodic 'spikes' observed in Tris-based media were interpreted in terms of cracking due to excessive stress in the surface region of the glass. Studies of the interactions of silicate glasses with metal ions in buffered media were extended to systems containing Al. Caps buffer was used to establish the pH. The procedures used are described and the results are given. Preliminary studies were initiated as to the feasibility of adding a slowly dissolving solid compound of the additive to the glass-water system to maintain a supply of dissolved additive. It appears that several magnesium compounds have a suitable combination of solubility and affinity towards silicate glass surfaces to have a pronounced retarding effect on the extraction of uranium from the glass. These preliminary findings raise the possibility that introducing a magnesium source into geologic repositories for nuclear waste glass in the form of a sparingly soluble Mg-based backfill material may cause a substantial reduction in the extent of long-term glass corrosion. The studies described also provide mechanistic understanding of the roles of various metal solutes in the leachant. Such understanding forms the basis for developing long-term predictions of nuclear waste glass durability under repository conditions. From what is known about natural highly reduced glasses such as tektites, it is clear that iron is dissolved as ferrous iron with little or no ferric iron. The reducing conditions were high enough to cause metallic iron to exsolve out of the glass in the form of submicroscopic spherules. As the nuclear waste glass is much less reduced, a study was initiated on other natural glasses in addition to the nuclear waste glass. Extensive measurements were carried out on these glasses in order to characterize their magnetic properties. Results of these studies are described.

When soils become sediments: Large-scale storage of soils in sandpits and lakes and the impact of reduction kinetics on heavy metals and arsenic release to groundwater.

PubMed

Vink, Jos P M; van Zomeren, Andre; Dijkstra, Joris J; Comans, Rob N J

2017-08-01

Simulating the storage of aerobic soils under water, the chemical speciation of heavy metals and arsenic was studied over a long-term reduction period. Time-dynamic and redox-discrete measurements in reactors were used to study geochemical changes. Large kinetic differences in the net-complexation quantities of heavy metals with sulfides was observed, and elevated pore water concentrations remained for a prolonged period (>1 year) specifically for As, B, Ba, Co, Mo, and Ni. Arsenic is associated to the iron phases as a co-precipitate or sorbed fraction to Fe-(hydr)oxides, and it is being released into solution as a consequence of the reduction of iron. The composition of dissolved organic matter (DOM) in reducing pore water was monitored, and relative contributions of fulvic, humic and hydrophylic compounds were measured via analytical batch procedures. Quantitative and qualitative shifts in organic compounds occur during reduction; DOM increased up to a factor 10, while fulvic acids become dominant over humic acids which disappear altogether as reduction progresses. Both the hydrophobic and hydrophilic fractions increase and may even become the dominant fraction. Reactive amorphous and crystalline iron phases, as well as dissolved FeII/FeIII speciation, were measured and used as input for the geochemical model to improve predictions for risk assessment to suboxic and anaerobic environments. The release of arsenic is related to readily reducible iron fractions that may be identified by 1 mM CaCl 2 extraction procedure. Including DOM concentration shifts and compositional changes during reduction significantly improved model simulations, enabling the prediction of peak concentrations and identification of soils with increased emission risk. Practical methods are suggested to facilitate the practice of environmentally acceptable soil storage under water. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrothermal alkali metal recovery process

DOEpatents

Wolfs, Denise Y.; Clavenna, Le Roy R.; Eakman, James M.; Kalina, Theodore

1980-01-01

In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles by treating them with a calcium or magnesium-containing compound in the presence of water at a temperature between about 250.degree. F. and about 700.degree. F. and in the presence of an added base to establish a pH during the treatment step that is higher than would otherwise be possible without the addition of the base. During the treating process the relatively high pH facilitates the conversion of water-insoluble alkali metal compounds in the alkali metal residues into water-soluble alkali metal constituents. The resultant aqueous solution containing water-soluble alkali metal constituents is then separated from the residue solids, which consist of the treated particles and any insoluble materials formed during the treatment step, and recycled to the gasification process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst. Preferably, the base that is added during the treatment step is an alkali metal hydroxide obtained by water washing the residue solids produced during the treatment step.

New plasmonic materials and fabrication tools for near- and mid-infrared sensing and spectroscopy

NASA Astrophysics Data System (ADS)

Black, Leo-Jay; Wang, Yudong; Abb, Martina; Boden, Stuart A.; de Groot, C. H.; Arbouet, Arnaud; Muskens, Otto L.

2015-05-01

With progress in nanofabrication, new strategies have become available that allow precise control of nanoscale optical fields using metallic nanostructures. Here we review recent progress in the control of optical resonances in metal nanostructures for applications in sensing and spectroscopy. We discuss the use of new techniques, such as helium-ion beam milling, which allow precise sculpting of nanometer-scale gaps; new materials such as metal oxides, which have a response somewhere inbetween that of conventional dielectrics and noble metals; and new designs such as L-shaped gap antennas which allow controlling the polarization state of light through near-field interactions between closely spaced antennas.

Antimicrobial action of chelating agents: repercussions on the microorganism development, virulence and pathogenesis.

PubMed

Santos, A L S; Sodre, C L; Valle, R S; Silva, B A; Abi-Chacra, E A; Silva, L V; Souza-Goncalves, A L; Sangenito, L S; Goncalves, D S; Souza, L O P; Palmeira, V F; d'Avila-Levy, C M; Kneipp, L F; Kellett, A; McCann, M; Branquinha, M H

2012-01-01

Infections caused by resistant microorganisms often fail to respond to conventional therapy, resulting in prolonged illness, increased treatment costs and greater risk of death. Consequently, the development of novel antimicrobial drugs is becoming more demanding every day since the existing drugs either have too many side-effects or they tend to lose effectiveness due to the selection of resistant strains. In view of these facts, a number of new strategies to obstruct vital biological processes of a microbial cell have emerged; one of these is focused on the use of metal-chelating agents, which are able to selectively disturb the essential metal metabolism of the microorganism by interfering with metal acquisition and bioavailability for crucial reactions. The chelation activity is able to inhibit the biological role of metal-dependent proteins (e.g., metalloproteases and transcription factors), disturbing the microbial cell homeostasis and culminating in the blockage of microbial nutrition, growth and development, cellular differentiation, adhesion to biotic (e.g., extracellular matrix components, cell and/or tissue) and abiotic (e.g., plastic, silicone and acrylic) structures as well as controlling the in vivo infection progression. Interestingly, chelating agents also potentiate the activity of classical antimicrobial compounds. The differences between the microorganism and host in terms of the behavior displayed in the presence of chelating agents could provide exploitable targets for the development of an effective chemotherapy for these diseases. Consequently, metal chelators represent a novel group of antimicrobial agents with potential therapeutic applications. This review will focus on the anti-fungal and anti-protozoan action of the most common chelating agents, deciphering and discussing their mode of action.

Metals and kidney autoimmunity.

PubMed Central

Bigazzi, P E

1999-01-01

The causes of autoimmune responses leading to human kidney pathology remain unknown. However, environmental agents such as microorganisms and/or xenobiotics are good candidates for that role. Metals, either present in the environment or administered for therapeutic reasons, are prototypical xenobiotics that cause decreases or enhancements of immune responses. In particular, exposure to gold and mercury may result in autoimmune responses to various self-antigens as well as autoimmune disease of the kidney and other tissues. Gold compounds, currently used in the treatment of patients with progressive polyarticular rheumatoid arthritis, can cause a nephrotic syndrome. Similarly, an immune-mediated membranous nephropathy frequently occurred when drugs containing mercury were commonly used. Recent epidemiologic studies have shown that occupational exposure to mercury does not usually result in autoimmunity. However, mercury induces antinuclear antibodies, sclerodermalike disease, lichen planus, or membranous nephropathy in some individuals. Laboratory investigations have confirmed that the administration of gold or mercury to experimental animals leads to autoimmune disease quite similar to that observed in human subjects exposed to these metals. In addition, studies of inbred mice and rats have revealed that a few strains are susceptible to the autoimmune effects of gold and mercury, whereas the majority of inbred strains are resistant. These findings have emphasized the importance of genetic (immunogenetic and pharmacogenetic) factors in the induction of metal-associated autoimmunity. (italic)In vitro(/italic) and (italic)in vivo(/italic) research of autoimmune disease caused by mercury and gold has already yielded valuable information and answered a number of important questions. At the same time it has raised new issues about possible immunostimulatory or immunosuppressive mechanisms of xenobiotic activity. Thus it is evident that investigations of metal-induced renal autoimmunity have the potential to produce new knowledge with relevance to autoimmune disease caused by xenobiotics in general as well as to idiopathic autoimmunity. PMID:10502542

designer phase transitions in lithium-based spinels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wouter Montfrooij

When electrons in a metal become correlated with each other, new cooperative behavior can arise. This correlation is magnified when the metal has magnetic ions embedded in it. These atomic magnets try to line up with each other, but in doing so actually create a correlation between the motions of conduction electrons. In turn, these correlated electron motions prevent the magnetic ions from aligning, even at zero Kelvin. When this competition is strongest (at the so-called quantum critical point-QCP) the response of the system can no longer be described using the text book theory for metals. In addition, a rangemore » of new phenomena has been seen to emerge in the vicinity of a QCP, such as heavy-fermion superconductivity, coexistence of magnetism and superconductivity and hyper-scaling. The main goal of our research is to try to unravel the details of the feedback mechanism between electron motion and magnetism that lies at the heart of this new physics. We have chosen lithium-based spinel structures as the most promising family of systems to achieve our goal. Known lithium-based spinels Li{sub x}M{sub 2}O{sub 4} [M=V, Ti and Mn] show a variety of ground states: heavy-fermion, superconducting, or geometrically frustrated local moment systems. Li{sub x}M{sub 2}O{sub 4} should be ideal systems for studying QCPs since their properties can easily be fine-tuned, simply by extracting some Li [which can be done without introducing disorder in the immediate surroundings of the magnetic ions]. The premise of the proposal was that since this Li-extraction can be done both in the metallic as well as in insulating compounds, that we can expand the types of quantum phase transitions that can be studied to beyond transitions in magnetic metals. The project called for developing a better understanding of quantum phase transitions by measuring all aspects of the electronic response of Li{sub x}M{sub 2}O{sub 4} by means of neutron scattering, giving microscopic information about the behavior of the individual magnetic moments and their interactions, as well as by macroscopic measurements. In addition, the aim was to synthesize new lithium-based spinel compounds by using other transition metals that exhibit both 3{sup +} and 4{sup +} valencies. Here we report on the progress we have made during the course of this grant both towards the stated goals and on new avenues that developed as a direct result of the data we collected during this grant.« less

Thin film Heusler compounds manganese nickel gallium

NASA Astrophysics Data System (ADS)

Jenkins, Catherine Ann

Multiferroic Heusler compounds Mn3--xNi xGa (x=0,1,2) have a tetragonal unit cell that can variously be used for magneto-mechanically coupled shape memory ( x=1,2) and spin-mechanical applications (x=0). The first fabrication of fully epitaxial thin films of these and electronically related compounds by sputtering is discussed. Traditional and custom lab characterization of the magnetic and temperature driven multiferroic behavior is augmented by more detailed synchrotron-based high energy photoemission spectroscopic techniques to describe the atomic and electronic structure. Integration of the MnNi2Ga magnetic shape memory compound in microwave patch antennas and active free-standing structures represents a fraction of the available and promising applications for these compounds. Prototype magnetic tunnel junctions are demonstrated by Mn3Ga electrodes with perpendicular anisotropy for spin torque transfer memory structures. The main body of the work concentrates on the definition and exploration of the material series Mn3--xNi xGa (x=0,1,2) and the relevant multiferroic phenomena exhibited as a function of preparation and external stimuli. Engineering results on each x=0,1,2 are presented with device prototypes where relevant. In the appendices the process of the materials design undertaken with the goal of developing new ternary intermetallics with enhanced properties is presented with a full exploration of the road from band structure calculations to device implementation. Cobalt based compounds in single crystal and nanoparticle form are fabricated with an eye to developing the production methods for new cobalt- and iron-based magnetic shape memory compounds for device applications in different forms. Mn2CoSn, a compound isolectronic and with similar atomic ordering to Mn2NiGa is experimentally determined to be a nearly half-metallic ferromagnet in contrast to the metallic ferrimagnetism in the parent compound. High energy photoemission spectroscopy is shown to be applicable to the analysis and observation of deeply buried metallic and semiconducting interface in an analysis of chalcopyrite solar cell heterolayers and model magnetic tunnel junctions with half-metalic Heusler electrodes.

Progress and Perspective of Electrocatalytic CO2 Reduction for Renewable Carbonaceous Fuels and Chemicals

PubMed Central

Zhang, Wenjun; Hu, Yi; Ma, Lianbo; Zhu, Guoyin; Wang, Yanrong; Xue, Xiaolan; Chen, Renpeng; Yang, Songyuan

2017-01-01

Abstract The worldwide unrestrained emission of carbon dioxide (CO2) has caused serious environmental pollution and climate change issues. For the sustainable development of human civilization, it is very desirable to convert CO2 to renewable fuels through clean and economical chemical processes. Recently, electrocatalytic CO2 conversion is regarded as a prospective pathway for the recycling of carbon resource and the generation of sustainable fuels. In this review, recent research advances in electrocatalytic CO2 reduction are summarized from both experimental and theoretical aspects. The referred electrocatalysts are divided into different classes, including metal–organic complexes, metals, metal alloys, inorganic metal compounds and carbon‐based metal‐free nanomaterials. Moreover, the selective formation processes of different reductive products, such as formic acid/formate (HCOOH/HCOO−), monoxide carbon (CO), formaldehyde (HCHO), methane (CH4), ethylene (C2H4), methanol (CH3OH), ethanol (CH3CH2OH), etc. are introduced in detail, respectively. Owing to the limited energy efficiency, unmanageable selectivity, low stability, and indeterminate mechanisms of electrocatalytic CO2 reduction, there are still many tough challenges need to be addressed. In view of this, the current research trends to overcome these obstacles in CO2 electroreduction field are summarized. We expect that this review will provide new insights into the further technique development and practical applications of CO2 electroreduction. PMID:29375961

Carbonate thermochemical cycle for the production of hydrogen

DOEpatents

Collins, Jack L [Knoxville, TN; Dole, Leslie R [Knoxville, TN; Ferrada, Juan J [Knoxville, TN; Forsberg, Charles W [Oak Ridge, TN; Haire, Marvin J [Oak Ridge, TN; Hunt, Rodney D [Oak Ridge, TN; Lewis, Jr, Benjamin E [Knoxville, TN; Wymer, Raymond G [Oak Ridge, TN

2010-02-23

The present invention is directed to a thermochemical method for the production of hydrogen from water. The method includes reacting a multi-valent metal oxide, water and a carbonate to produce an alkali metal-multi-valent metal oxide compound, carbon dioxide, and hydrogen.

COMPETITIVE INFLUENCE OF PHOSPHORUS AND CALCIUM ON PB IN-VITRO BIOAVAILABILITY

EPA Science Inventory

The bioavailability of a metal is heavily related to the speciation of the particular metal. Further, the complexity of examining metal bioavailability is compounded by the presence of competitive ions. Thus, equally contaminated soils with varying concentrations of competitive e...

Ambient Air Monitoring for Sulfur Compounds

ERIC Educational Resources Information Center

Forrest, Joseph; Newman, Leonard

1973-01-01

A literature review of analytical techniques available for the study of compounds at low concentrations points up some of the areas where further research is needed. Compounds reviewed are sulfur dioxide, sulfuric acid, ammonium sulfate and bisulfate, metal sulfates, hydrogen sulfide, and organic sulfides. (BL)

Mechanochemical processing for metals and metal alloys

DOEpatents

Froes, Francis H.; Eranezhuth, Baburaj G.; Prisbrey, Keith

2001-01-01

A set of processes for preparing metal powders, including metal alloy powders, by ambient temperature reduction of a reducible metal compound by a reactive metal or metal hydride through mechanochemical processing. The reduction process includes milling reactants to induce and complete the reduction reaction. The preferred reducing agents include magnesium and calcium hydride powders. A process of pre-milling magnesium as a reducing agent to increase the activity of the magnesium has been established as one part of the invention.

Friction welded nonconsumable electrode assembly and use thereof for electrolytic production of metals and silicon

DOEpatents

Byrne, Stephen C.; Ray, Siba P.; Rapp, Robert A.

1984-01-01

A nonconsumable electrode assembly suitable for use in the production of metal by electrolytic reduction of a metal compound dissolved in a molten salt, the assembly comprising a metal conductor and a ceramic electrode body connected by a friction weld between a portion of the body having a level of free metal or metal alloy sufficient to effect such a friction weld and a portion of the metal conductor.

FY12 ARRA-NRAP Report – Studies to Support Risk Assessment of Geologic Carbon Sequestration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cantrell, Kirk J.; Shao, Hongbo; Thompson, C. J.

2011-09-27

This report summarizes results of research conducted during FY2012 to support the assessment of environmental risks associated with geologic carbon dioxide (CO2) sequestration and storage. Several research focus areas are ongoing as part of this project. This includes the quantification of the leachability of metals and organic compounds from representative CO2 storage reservoir and caprock materials, the fate of metals and organic compounds after release, and the development of a method to measure pH in situ under supercritical CO2 (scCO2) conditions. Metal leachability experiments were completed on 6 different rock samples in brine in equilibrium with scCO2 at representative geologicmore » reservoir conditions. In general, the leaching of RCRA metals and other metals of concern was found to be limited and not likely to be a significant issue (at least, for the rocks tested). Metals leaching experiments were also completed on 1 rock sample with scCO2 containing oxygen at concentrations of 0, 1, 5, and 10% to simulate injection of CO2 originating from the oxy-fuel combustion process. Significant differences in the leaching behavior of certain metals were observed when oxygen is present in the CO2. These differences resulted from oxidation of sulfides, release of sulfate, ferric iron and other metals, and subsequent precipitation of iron oxides and some sulfates such as barite. Experiments to evaluate the potential for mobilization of organic compounds from representative reservoir materials and cap rock and their fate in porous media (quartz sand) have been conducted. Results with Fruitland coal and Gothic shale indicate that lighter organic compounds were more susceptible to mobilization by scCO2 compared to heavier compounds. Alkanes demonstrated very low extractability by scCO2. No significant differences were observed between the extractability of organic compounds by dry or water saturated scCO2. Reaction equilibrium appears to have been reached by 96 hours. When the scCO2 was released from the reactor, less than 60% of the injected lighter compounds (benzene, toluene) were transported through dry sand column by the CO2, while more than 90% of the heavier organics were trapped in the sand column. For wet sand columns, most (80% to 100%) of the organic compounds injected into the sand column passed through, except for naphthalene which was substantial removed from the CO2 within the column. A spectrophotometric method was developed to measure pH in brines in contact with scCO2. This method provides an alternative to fragile glass pH electrodes and thermodynamic modeling approaches for estimating pH. The method was tested in simulated reservoir fluids (CO2–NaCl–H2O) at different temperatures, pressures, and ionic strength, and the results were compared with other experimental studies and geochemical models. Measured pH values were generally in agreement with the models, but inconsistencies were present between some of the models.« less

Bioremediation of trace organic compounds found in precious metals refineries' wastewaters: a review of potential options.

PubMed

Barbosa, V L; Tandlich, R; Burgess, J E

2007-07-01

Platinum group metal (PGM) refining processes produce large quantities of wastewater, which is contaminated with the compounds that make up the solvents/extractants mixtures used in the process. These compounds often include solvesso, beta-hydroxyxime, amines, amides and methyl isobutyl ketone. A process to clean up PGM refinery wastewaters so that they could be re-used in the refining process would greatly contribute to continual water storage problems and to cost reduction for the industry. Based on the concept that organic compounds that are produced biologically can be destroyed biologically, the use of biological processes for the treatment of organic compounds in other types of waste stream has been favoured in recent years, owing to their low cost and environmental acceptability. This review examines the available biotechnologies and their effectiveness for treating compounds likely to be contained in precious metal extraction process wastewaters. The processes examined include: biofilters, fluidized bed reactors, trickle-bed bioreactors, bioscrubbers, two-phase partitioning bioreactors, membrane bioreactors and activated sludge. Although all processes examined showed adequate to excellent removal of organic compounds from various gaseous and fewer liquid waste streams, there was a variation in their effectiveness. Variations in performance of laboratory-scale biological processes are probably due to the inherent change in the microbial population composition due to selection pressure, environmental conditions and the time allowed for adaptation to the organic compounds. However, if these factors are disregarded, it can be established that activated sludge and membrane bioreactors are the most promising processes for use in the treatment of PGM refinery wastewaters.

Exploring Trends in Metal-Metal Bonding, Spectroscopic Properties, and Conformational Flexibility in a Series of Heterobimetallic Ti/M and V/M Complexes (M = Fe, Co, Ni, and Cu).

PubMed

Wu, Bing; Wilding, Matthew J T; Kuppuswamy, Subramaniam; Bezpalko, Mark W; Foxman, Bruce M; Thomas, Christine M

2016-12-05

To understand the metal-metal bonding and conformational flexibility of first-row transition metal heterobimetallic complexes, a series of heterobimetallic Ti/M and V/M complexes (M = Fe, Co, Ni, and Cu) have been investigated. The titanium tris(phosphinoamide) precursors ClTi(XylNP i Pr 2 ) 3 (1) and Ti(XylNP i Pr 2 ) 3 (2) have been used to synthesize Ti/Fe (3), Ti/Ni (4, 4 THF ), and Ti/Cu (5) heterobimetallic complexes. A series of V/M (M = Fe (7), Co (8), Ni (9), and Cu (10)) complexes have been generated starting from the vanadium tris(phosphinoamide) precursor V(XylNP i Pr 2 ) 3 (6). The new heterobimetallic complexes were characterized and studied by NMR spectroscopy, X-ray crystallography, electron paramagnetic resonance, and Mössbauer spectroscopy, where applicable, and computational methods (DFT). Compounds 3, 4 THF , 7, and 8 are C 3 -symmetric with three bridging phosphinoamide ligands, while compounds 9 and 10 adopt an asymmetric geometry with two bridging phosphinoamides and one phosphinoamide ligand bound η 2 to vanadium. Compounds 4 and 5, on the other hand, are asymmetric in the solid state but show evidence for fluxional behavior in solution. A correlation is established between conformational flexibility and metal-metal bond order, which has important implications for the future reactivity of these and other heterobimetallic molecules.

Spectro Analytical, Computational and In Vitro Biological Studies of Novel Substituted Quinolone Hydrazone and it's Metal Complexes.

PubMed

Nagula, Narsimha; Kunche, Sudeepa; Jaheer, Mohmed; Mudavath, Ravi; Sivan, Sreekanth; Ch, Sarala Devi

2018-01-01

Some novel transition metal [Cu (II), Ni (II) and Co (II)] complexes of nalidixic acid hydrazone have been prepared and characterized by employing spectro-analytical techniques viz: elemental analysis, 1 H-NMR, Mass, UV-Vis, IR, TGA-DTA, SEM-EDX, ESR and Spectrophotometry studies. The HyperChem 7.5 software was used for geometry optimization of title compound in its molecular and ionic forms. Quantum mechanical parameters, contour maps of highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) and corresponding binding energy values were computed using semi empirical single point PM3 method. The stoichiometric equilibrium studies of metal complexes carried out spectrophotometrically using Job's continuous variation and mole ratio methods inferred formation of 1:2 (ML 2 ) metal complexes in respective systems. The title compound and its metal complexes screened for antibacterial and antifungal properties, exemplified improved activity in metal complexes. The studies of nuclease activity for the cleavage of CT- DNA and MTT assay for in vitro cytotoxic properties involving metal complexes exhibited high activity. In addition, the DNA binding properties of Cu (II), Ni (II) and Co (II) complexes investigated by electronic absorption and fluorescence measurements revealed their good binding ability and commended agreement of K b values obtained from both the techniques. Molecular docking studies were also performed to find the binding affinity of synthesized compounds with DNA (PDB ID: 1N37) and "Thymidine phosphorylase from E.coli" (PDB ID: 4EAF) protein targets.

First report of phytochelatins in a mushroom: induction of phytochelatins by metal exposure in Boletus edulis.

PubMed

Collin-Hansen, Christian; Pedersen, Sindre A; Andersen, Rolf A; Steinnes, Eiliv

2007-01-01

Some species of macromycetes (mushrooms) consistently are found to contain high concentrations of toxic metals such as cadmium (Cd) and mercury (Hg), and consumption of wild-growing mushrooms is acknowledged as a significant source for Cd and Hg in humans. Yet little is known about the speciation of Cd and Hg in mushroom tissues. Here we present the first evidence of peptides of the phytochelatin family being responsible for binding a large fraction of Cd in caps of the macromycete Boletus edulis exposed to excess metals. Concentrations of Cd, Zn, Cu and Hg, as well as cytosolic Cd-binding capacity (CCBC), glutathione (GSH) and free proline (Pro) were quantified in fruiting bodies of B. edulis differentially exposed to a wide range of metals. Metal distribution among cytosolic compounds were investigated by size exclusion chromatography (SEC), followed by metal determinations with atomic absorption chromatography (AAS) and HR-ICP-MS. Cd-binding compounds in SEC elutates were investigated further by high performance liquid chromatography-mass spectrometry (HPLC-MS). CCBC was >90 times higher in the exposed group relative to the reference group (Mann-Whitney's P < 0.001), whereas concentrations of free Pro were almost identical for the two groups. For the whole study selection, CCBC correlated positively with metal exposure (Spearman's P < 0.001 for all four metals), suggesting dose-dependent induction of Cd-binding compounds by exposure to these metals, possibly as a defense mechanism. The presence of phytochelatins (PCs), a family of cystein-rich oligopeptides, was confirmed in Cd-containing SEC fractions by HPLC-MS. The appearance of more complex PCs was coupled to declining concentrations of GSH. To our knowledge this is the first report demonstrating the presence of PCs in a macromycete.

Salts of alkali metal anions and process of preparing same

DOEpatents

Dye, James L.; Ceraso, Joseph M.; Tehan, Frederick J.; Lok, Mei Tak

1978-01-01

Compounds of alkali metal anion salts of alkali metal cations in bicyclic polyoxadiamines are disclosed. The salts are prepared by contacting an excess of alkali metal with an alkali metal dissolving solution consisting of a bicyclic polyoxadiamine in a suitable solvent, and recovered by precipitation. The salts have a gold-color crystalline appearance and are stable in a vacuum at -10.degree. C. and below.

Novel iridium (III)‑derived organometallic compound for the inhibition of human platelet activation.

PubMed

Shyu, Kou-Gi; Velusamy, Marappan; Hsia, Chih-Wei; Yang, Chih-Hao; Hsia, Chih-Hsuan; Chou, Duen-Suey; Jayakumar, Thanasekaran; Sheu, Joen-Rong; Li, Jiun-Yi

2018-05-01

Since cisplatin achieved clinical success, transition metal platinum (Pt) drugs have been effectively used for the treatment of cancer. Iridium (Ir) compounds are considered to be potential alternatives to Pt compounds, as they possess promising anticancer effects with minor side effects. Platelet activation is associated with the metastasis and progression of cancer, and also with arterial thrombosis. Therefore, it is necessary to develop novel, effective antithrombotic agents. An Ir (III)‑derived complex, [Ir (Cp*) 1‑(2‑pyridyl)‑3‑(3‑methoxyphenyl)imidazo[1,5‑a]pyridine Cl]BF4 (Ir‑3), was developed as a novel antiplatelet drug. Ir‑3 exerted more potent inhibitory activity on platelet aggregation stimulated by collagen compared with other agonists, including thrombin. In collagen‑activated platelets, Ir‑3 also inhibited adenosine trisphosphate release, intracellular Ca+2 mobilization and surface P‑selectin expression, as well as the phosphorylation of phospholipase Cγ2 (PLCγ2), protein kinase C (PKC), protein kinase B (Akt) and c‑Jun N‑terminal kinase (JNK) 1, but not p38 mitogen‑activated protein kinase or extracellular signal‑regulated kinases. Ir‑3 did not markedly affect phorbol 12, 13‑dibutyrate‑stimulated platelet aggregation. Neither the adenylate cyclase inhibitor SQ22536 nor the guanylate cyclase inhibitor 1H‑[1, 2, 4] oxadiazolo [4,3‑a]quinoxalin‑1‑one significantly reversed the Ir‑3‑mediated inhibition of platelet aggregation. Furthermore, Ir‑3 had no considerable diminishing effects on OH radical signals in collagen‑stimulated platelets or Fenton reaction solution. In conclusion, Ir‑3 serves a novel function in the inhibition of platelet aggregation through inhibiting the PLCγ2‑PKC cascade, and the subsequent suppression of Akt and JNK1 activation. Therefore, Ir‑3 may be a potential novel therapeutic agent for the treatment of thromboembolic disorders, or the interplay between platelets and tumor cells which contributes to tumor cell proliferation and progression.

Electronic structure of negative charge transfer CaFeO3 across the metal-insulator transition

NASA Astrophysics Data System (ADS)

Rogge, Paul C.; Chandrasena, Ravini U.; Cammarata, Antonio; Green, Robert J.; Shafer, Padraic; Lefler, Benjamin M.; Huon, Amanda; Arab, Arian; Arenholz, Elke; Lee, Ho Nyung; Lee, Tien-Lin; Nemšák, Slavomír; Rondinelli, James M.; Gray, Alexander X.; May, Steven J.

2018-01-01

We investigated the metal-insulator transition for epitaxial thin films of the perovskite CaFeO3, a material with a significant oxygen ligand hole contribution to its electronic structure. We find that biaxial tensile and compressive strain suppress the metal-insulator transition temperature. By combining hard x-ray photoelectron spectroscopy, soft x-ray absorption spectroscopy, and density functional calculations, we resolve the element-specific changes to the electronic structure across the metal-insulator transition. We demonstrate that the Fe sites undergo no observable spectroscopic change between the metallic and insulating states, whereas the O electronic configuration undergoes significant changes. This strongly supports the bond-disproportionation model of the metal-insulator transition for CaFeO3 and highlights the importance of ligand holes in its electronic structure. By sensitively measuring the ligand hole density, however, we find that it increases by ˜5 -10 % in the insulating state, which we ascribe to a further localization of electron charge on the Fe sites. These results provide detailed insight into the metal-insulator transition of negative charge transfer compounds and should prove instructive for understanding metal-insulator transitions in other late transition metal compounds such as the nickelates.

Adsorption of heavy metal from aqueous solution by dehydrated root powder of long-root Eichhornia crassipes.

PubMed

Li, Qiang; Chen, Bo; Lin, Peng; Zhou, Jiali; Zhan, Juhong; Shen, Qiuying; Pan, Xuejun

2016-01-01

The root powder of long-root Eichhornia crassipes, as a new kind of biodegradable adsorbent, has been tested for aqueous adsorption of Pb, Zn, Cu, and Cd. From FT-IR, we found that the absorption peaks of phosphorous compounds, carbonyl, and nitrogenous compounds displayed obvious changes before and after adsorption which illustrated that plant characteristics may play a role in binding with metals. Surface properties and morphology of the root powders have been characterized by means of SEM and BET. Energy spectrum analysis showed that the metals were adsorbed on root powders after adsorption. Then, optimum quantity of powder, pH values, and metal ion concentrations in single-system and multi-system were detected to discuss the characteristics and mechanisms of metal adsorption. Freundlich model and the second-order kinetics equation could well describe the adsorption of heavy metals in single-metal system. The adsorption of Pb, Zn, and Cd in the multi-metal system decreased with the concentration increased. At last, competitive adsorption of every two metals on root powder proved that Cu and Pb had suppressed the adsorption performance of Cd and Zn.

Powder X-ray diffraction, infrared and 13C NMR spectroscopic studies of the homologous series of some solid-state zinc(II) and sodium(I) n-alkanoates

NASA Astrophysics Data System (ADS)

Nelson, Peter N.; Taylor, Richard A.

2015-03-01

A comparative study of the room temperature molecular packing and lattice structures for the homologous series of zinc(II) and sodium(I) n-alkanoates adduced from Fourier transform infrared and solid-state 13C NMR spectroscopic data in conjunction with X-ray powder diffraction measurements is carried out. For zinc carboxylates, metal-carboxyl bonding is via asymmetric bridging bidentate coordination whilst for the sodium adducts, coordination is via asymmetric chelating bidentate bonding. All compounds are packed in a monoclinic crystal system. Furthermore, the fully extended all-trans hydrocarbon chains are arranged as lamellar bilayers. For zinc compounds, there is bilayer overlap, for long chain adducts (nc > 8) but not for sodium compounds where methyl groups from opposing layers in the lamellar are only closely packed. Additionally, the hydrocarbon chains are extended along the a-axis of the unit cell for zinc compounds whilst for sodium carboxylates they are extended along the c-axis. These packing differences are responsible for different levels of Van der Waals effects in the lattices of these two series of compounds, hence, observed odd-even alternation is different. The significant difference in lattice packing observed for these two series of compounds is proposed to be due to the difference in metal-carboxyl coordination mode, arising from the different electronic structure of the central metal ions.

Metal Cationization Extractive Electrospray Ionization Mass Spectrometry of Compounds Containing Multiple Oxygens

NASA Astrophysics Data System (ADS)

Swanson, Kenneth D.; Spencer, Sandra E.; Glish, Gary L.

2017-06-01

Extractive electrospray ionization is an ambient ionization technique that allows real-time sampling of liquid samples, including organic aerosols. Similar to electrospray ionization, the composition of the electrospray solvent used in extractive electrospray ionization can easily be altered to form metal cationized molecules during ionization simply by adding a metal salt to the electrospray solvent. An increase in sensitivity is observed for some molecules that are lithium, sodium, or silver cationized compared with the protonated molecule formed in extractive electrospray ionization with an acid additive. Tandem mass spectrometry of metal cationized molecules can also significantly improve the ability to identify a compound. Tandem mass spectrometry of lithium and silver cationized molecules can result in an increase in the number and uniqueness of dissociation pathways relative to [M + H]+. These results highlight the potential for extractive electrospray ionization with metal cationization in analyzing complex aerosol mixtures. [Figure not available: see fulltext.

Pressure induced enhancement of the magnetic ordering temperature in rhenium(IV) monomers

NASA Astrophysics Data System (ADS)

Woodall, Christopher H.; Craig, Gavin A.; Prescimone, Alessandro; Misek, Martin; Cano, Joan; Faus, Juan; Probert, Michael R.; Parsons, Simon; Moggach, Stephen; Martínez-Lillo, José; Murrie, Mark; Kamenev, Konstantin V.; Brechin, Euan K.

2016-12-01

Materials that demonstrate long-range magnetic order are synonymous with information storage and the electronics industry, with the phenomenon commonly associated with metals, metal alloys or metal oxides and sulfides. A lesser known family of magnetically ordered complexes are the monometallic compounds of highly anisotropic d-block transition metals; the `transformation' from isolated zero-dimensional molecule to ordered, spin-canted, three-dimensional lattice being the result of through-space interactions arising from the combination of large magnetic anisotropy and spin-delocalization from metal to ligand which induces important intermolecular contacts. Here we report the effect of pressure on two such mononuclear rhenium(IV) compounds that exhibit long-range magnetic order under ambient conditions via a spin canting mechanism, with Tc controlled by the strength of the intermolecular interactions. As these are determined by intermolecular distance, `squeezing' the molecules closer together generates remarkable enhancements in ordering temperatures, with a linear dependence of Tc with pressure.

A new approach for the recovery of precious metals from solution and from leachates derived from electronic scrap.

PubMed

Macaskie, L E; Creamer, N J; Essa, A M M; Brown, N L

2007-03-01

A new approach is described for the recovery of precious metals (PMs: Au, Pd and Ag) with >99% efficiency from aqueous solution utilising biogas produced during the aerobic growth of Klebsiella pneumoniae. Gold was recovered from electronic scrap leachate ( approximately 95%) by this method, with some selectivity against Cu. The recovered PM solids all contained metal and sulphur as determined by energy dispersive X-ray microanalysis (EDX). X-ray powder diffraction analysis (XRD) showed no crystalline metal sulphur compounds but a crystalline palladium amine was recorded. Silver was recovered as a sulphide (found by EDX), carbonate and oxide (found by XRD). EDX analysis of the Au-precipitate showed mainly gold and sulphur, with some metallic Au(0) detected by XRD. The gold compound was shock-sensitive; upon grinding it detonated to leave a sooty black deposit.

Benzene contamination at a metal plating facility

NASA Astrophysics Data System (ADS)

Memon, B. A.; Burston, M. R.

2005-08-01

A metal plating facility in central Kentucky was required to complete a RCRA Facility Investigation to address a number of Solid Waste Management Units at the site. Twenty monitoring wells were installed at the facility. Ground water from the wells was sampled for total and dissolved metals, polychlorinated biphenyls, acid extractable compounds, base neutral compounds, and volatile organic compounds. Unexpectedly, relatively large concentrations of benzene, up to 120 μg/l, were detected in samples from some of the wells, including wells that should have been hydraulically upgradient from the facility. As a result of the detection of benzene, the facility completed an investigation to identify the source. A nearby facility had completed a gasoline underground storage tank (UST) closure at about the time of the installation of the 20 wells. Reportedly the UST had small holes when removed. Three potential pathways of migration (a ditch, sanitary sewer, and a sink hole) from the nearby facility to the metal-plating facility and residual soils with very large concentrations of benzene, toluene, ethylbenzene, and xylenes have been identified.

Computational and Physical Analysis of Catalytic Compounds

NASA Astrophysics Data System (ADS)

Wu, Richard; Sohn, Jung Jae; Kyung, Richard

2015-03-01

Nanoparticles exhibit unique physical and chemical properties depending on their geometrical properties. For this reason, synthesis of nanoparticles with controlled shape and size is important to use their unique properties. Catalyst supports are usually made of high-surface-area porous oxides or carbon nanomaterials. These support materials stabilize metal catalysts against sintering at high reaction temperatures. Many studies have demonstrated large enhancements of catalytic behavior due to the role of the oxide-metal interface. In this paper, the catalyzing ability of supported nano metal oxides, such as silicon oxide and titanium oxide compounds as catalysts have been analyzed using computational chemistry method. Computational programs such as Gamess and Chemcraft has been used in an effort to compute the efficiencies of catalytic compounds, and bonding energy changes during the optimization convergence. The result illustrates how the metal oxides stabilize and the steps that it takes. The graph of the energy computation step(N) versus energy(kcal/mol) curve shows that the energy of the titania converges faster at the 7th iteration calculation, whereas the silica converges at the 9th iteration calculation.

Ferroelectric properties of oxalate and phenanthroline based 1-D single chain molecular magnet [{FeII(Δ)FeII(Λ)}0.5{CrII(Δ)CrII(Λ)}0.5(ox)2(phen)2

NASA Astrophysics Data System (ADS)

Bhatt, Pramod; Mukadam, M. D.; Mandal, B. P.; Yusuf, S. M.

2018-04-01

The one-dimensional (1-D) single chain molecular magnet [{FeII(Δ)FeII(Λ)}0.5{CrII(Δ)CrII(Λ)}0.5(ox)2(phen)2] is hydrothermally synthesized using oxalate (ox) and phenanthroline (phen) ligands with transition metal ions (Fe and Cr). The compound is characterized using x-ray diffraction, dc magnetization measurements and P-E ferroelectric loop measurements. The diffraction analysis using Rietveld refinement confirms a single phase formation of the compound in monoclinic structure with space group of P21. The compound crystallizes in 1-D chain like structure containing two different crystallographic sites of metal ions (Δ- and Λ-), which are bridged by the ox ligand and Phen ligand. These two metals site are different in bond length and bond angles results lattice distortions. The lattice distortion induces ferroelectric behavior in the compound which is discussed in terms of lattice distortion induced dipole moments.

Universal, In Situ Transformation of Bulky Compounds into Nanoscale Catalysts by High-Temperature Pulse.

PubMed

Xu, Shaomao; Chen, Yanan; Li, Yiju; Lu, Aijiang; Yao, Yonggang; Dai, Jiaqi; Wang, Yanbin; Liu, Boyang; Lacey, Steven D; Pastel, Glenn R; Kuang, Yudi; Danner, Valencia A; Jiang, Feng; Fu, Kun Kelvin; Hu, Liangbing

2017-09-13

The synthesis of nanoscale metal compound catalysts has attracted much research attention in the past decade. The challenges of preparation of the metal compound include the complexity of the synthesis process and difficulty of precise control of the reaction conditions. Herein, we report an in situ synthesis of nanoparticles via a high-temperature pulse method where the bulk material acts as the precursor. During the process of rapid heating and cooling, swift melting, anchoring, and recrystallization occur, resulting in the generation of high-purity nanoparticles. In our work, the cobalt boride (Co 2 B) nanoparticles with a diameter of 10-20 nm uniformly anchored on the reduced graphene oxide (rGO) nanosheets were successfully prepared using the high temperature pulse method. The as-prepared Co 2 B/rGO composite displayed remarkable electrocatalytic performance for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). We also prepared molybdenum disulfide (MoS 2 ) and cobalt oxide (Co 3 O 4 ) nanoparticles, thereby demonstrating that the high-temperature pulse is a universal method to synthesize ultrafine metal compound nanoparticles.

Synthesis of 4-substituted-trans-1, 2-diaminocyclohexyl polyaminocarboxylate metal chelating agents for the preparation of stable radiometal antibody immunoconjugates for therapy and SPECT and PET imaging

DOEpatents

Mease, R.C.; Mausner, L.F.; Srivastava, S.C.

1994-03-08

Cyclo agents are described which are useful in forming antibody-metal conjugates which are used for diagnostic and therapeutic purposes. New compounds and processes of forming these compounds are disclosed including 4-haloacetamido-trans-1,2diaminocyclohexyl polyaminocarboxylate and 4-isothiocyanato-trans-1,2diamino cyclohexane-N,N,N',N'-tetra acetic acid. No Drawings

Synthesis of 4-substituted-trans-1,2-diaminocyclohexyl polyaminocarboxylate metal chelating agents for the preparation of stable radiometal antibody immunoconjugates for therapy and SPECT and PET imaging

DOEpatents

Mease, R.C.; Kolsky, K.L.; Mausner, L.F.; Srivastava, S.C.

1997-06-03

Cyclohexyl chelating agents useful in forming antibody-metal conjugates which are used for diagnostic and therapeutic purposes are synthesized. New compounds and processes of forming these compounds are disclosed including 4-haloacetamido-trans-1,2-diaminocyclohexyl polyaminocarboxylate and 4-isothiocyanato-trans-1,2-diamino cyclohexane-N,N,N{prime},N{prime}-tetra acetic acid.

Actinide halide complexes

DOEpatents

Avens, Larry R.; Zwick, Bill D.; Sattelberger, Alfred P.; Clark, David L.; Watkin, John G.

1992-01-01

A compound of the formula MX.sub.n L.sub.m wherein M is a metal atom selected from the group consisting of thorium, plutonium, neptunium or americium, X is a halide atom, n is an integer selected from the group of three or four, L is a coordinating ligand selected from the group consisting of aprotic Lewis bases having an oxygen-, nitrogen-, sulfur-, or phosphorus-donor, and m is an integer selected from the group of three or four for monodentate ligands or is the integer two for bidentate ligands, where the sum of n+m equals seven or eight for monodentate ligands or five or six for bidentate ligands, a compound of the formula MX.sub.n wherein M, X, and n are as previously defined, and a process of preparing such actinide metal compounds including admixing the actinide metal in an aprotic Lewis base as a coordinating solvent in the presence of a halogen-containing oxidant, are provided.

Soluble Nutrient and Trace Metal Fluxes from Aerosol Dry Deposition to Elkhorn Slough, CA

NASA Astrophysics Data System (ADS)

Gray, E. T.; Paytan, A.; Haskins, J.

2009-12-01

Atmospheric deposition has been widely recognized as a source of pollutants and nutrients to coastal ecosystems. Specifically, deposition includes nitrogen compounds, sulfur compounds, mercury, pesticides, phosphate, trace metals and other toxic compounds that can travel great distances in aerosols. These components can come from both natural (volcanoes, mineral dust, forest fires) and anthropogenic (fossil fuels, chemical byproducts, incineration of waste) sources. These pollutants may affect ecosystem health and water quality with environmental impacts such as eutrophication, contaminated fish and harmful algal blooms. In this study we focus on dry deposition to Elkhorn Slough, California. Size fractionated aerosol samples (PM 2.5 and PM 10) collected continuously over a seven day period using a cascade impactor are used along with a deposition model to determine the soluble nutrient and trace metal fluxes on the Elkhorn Slough ecosystem. Atmospheric deposition inputs will be compared to other sources and their potential impact evaluated.

Method of preparing a positive electrode for an electrochemical cell

DOEpatents

Tomczuk, Zygmunt

1979-01-01

A method of preparing an electrochemical cell including a metal sulfide as the positive electrode reactant and lithium alloy as the negative electrochemical reactant with an alkali metal, molten salt electrolyte is disclosed which permits the assembly to be accomplished in air. The electrode reactants are introduced in the most part as a sulfide of lithium and the positive electrode metal in a single-phase compound. For instance, Li.sub.2 FeS.sub.2 is a single-phase compound that is produced by the reaction of Li.sub.2 S and FeS. This compound is an intermediate in the positive electrode cycle from FeS.sub.2 to Fe and Li.sub.2 S. Its use minimizes volumetric changes from the assembled to the charged and discharged conditions of the electrode and minimizes electrode material interaction with air and moisture during assembly.

Actinide halide complexes

DOEpatents

Avens, L.R.; Zwick, B.D.; Sattelberger, A.P.; Clark, D.L.; Watkin, J.G.

1992-11-24

A compound is described of the formula MX[sub n]L[sub m] wherein M is a metal atom selected from the group consisting of thorium, plutonium, neptunium or americium, X is a halide atom, n is an integer selected from the group of three or four, L is a coordinating ligand selected from the group consisting of aprotic Lewis bases having an oxygen-, nitrogen-, sulfur-, or phosphorus-donor, and m is an integer selected from the group of three or four for monodentate ligands or is the integer two for bidentate ligands, where the sum of n+m equals seven or eight for monodentate ligands or five or six for bidentate ligands. A compound of the formula MX[sub n] wherein M, X, and n are as previously defined, and a process of preparing such actinide metal compounds are described including admixing the actinide metal in an aprotic Lewis base as a coordinating solvent in the presence of a halogen-containing oxidant.

Performance of metal compound on thermolysis and electrolysis on sugar industries waste water treatment: COD and color removal with sludge analysis (batch-experiment)

NASA Astrophysics Data System (ADS)

Sahu, Omprakash

2017-10-01

The sugar cane industry is one of the most water demanding industries. Sugar industries consume and generate excess amount of water. The generated water contains organic compounds, which would cause pollution. The aim of this research work is to study the effectiveness of metal compound for treatment of sugar industry waste water by thermolysis and electrolysis process. The result shows ferrous metal catalyst shows 80 and 85 % chemical oxygen demand and color removal at pH 6, optimum mass loading 4 kg/m3, treatment temperature 85 °C and treatment time 9 h. When ferrous material was used as electrode, maximum 81 % chemical oxygen demand and 84 % color removal at pH 6, current density 156 Am-2, treatment time 120 min and anode consumption 0.7 g for 1.5 L wastewater were obtained.

Improved hydrous oxide ion-exchange compound catalysts

DOEpatents

Dosch, R.G.; Stephens, H.P.

1986-04-09

Disclosed is a catalytic material of improved activity which comprises a hydrous, alkali metal or alkaline earth metal or quaternary ammonium titanate, zirconate, niobate, or tantalate, in which the metal or ammonium cations have been exchanged with a catalytically effective quantity of a catalyst metal, and which has been subsequently treated with a solution of a Bronsted acid.

Process for making transition metal nitride whiskers

DOEpatents

Bamberger, C.E.

1988-04-12

A process for making metal nitrides, particularly titanium nitride whiskers, using a cyanide salt as a reducing agent for a metal compound in the presence of an alkali metal oxide. Sodium cyanide, various titanates and titanium oxide mixed with sodium oxide react to provide titanium nitride whiskers that can be used as reinforcement to ceramic composites. 1 fig., 1 tab.

40 CFR 710.4 - Scope of the inventory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... upon use of curable plastic or rubber molding compounds, inks, drying oils, metal finishing compounds... impart a specific physicochemical characteristic, functions as intended. (8) Chemical substances which...

40 CFR 710.4 - Scope of the inventory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... modifier, pH neutralizer, sequesterant, coagulant, flocculant, fire retardant, lubricant, chelating agent... upon use of curable plastic or rubber molding compounds, inks, drying oils, metal finishing compounds...

Systems and methods for producing metal clusters; functionalized surfaces; and droplets including solvated metal ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooks, Robert Graham; Li, Anyin; Luo, Qingjie

The invention generally relates to systems and methods for producing metal clusters; functionalized surfaces; and droplets including solvated metal ions. In certain aspects, the invention provides methods that involve providing a metal and a solvent. The methods additionally involve applying voltage to the solvated metal to thereby produce solvent droplets including ions of the metal containing compound, and directing the solvent droplets including the metal ions to a target. In certain embodiments, once at the target, the metal ions can react directly or catalyze reactions.

Systems and methods for producing metal clusters; functionalized surfaces; and droplets including solvated metal ions

DOEpatents

Cooks, Robert Graham; Li, Anyin; Luo, Qingjie

2017-01-24

The invention generally relates to systems and methods for producing metal clusters; functionalized surfaces; and droplets including solvated metal ions. In certain aspects, the invention provides methods that involve providing a metal and a solvent. The methods additionally involve applying voltage to the solvated metal to thereby produce solvent droplets including ions of the metal containing compound, and directing the solvent droplets including the metal ions to a target. In certain embodiments, once at the target, the metal ions can react directly or catalyze reactions.

Depositing nanometer-sized particles of metals onto carbon allotropes

NASA Technical Reports Server (NTRS)

Delozier, Donavon M. (Inventor); Fallbach, Michael J. (Inventor); Smith, Joseph G. (Inventor); Watson, Kent A. (Inventor); Ghose, Sayata (Inventor); Connell, John W. (Inventor)

2010-01-01

A process for depositing nanometer-sized metal particles onto a substrate in the absence of aqueous solvents, organic solvents, and reducing agents, and without any required pre-treatment of the substrate, includes preparing an admixture of a metal compound and a substrate by dry mixing a chosen amount of the metal compound with a chosen amount of the substrate; and supplying energy to the admixture in an amount sufficient to deposit zero valance metal particles onto the substrate. This process gives rise to a number of deposited metallic particle sizes which may be controlled. The compositions prepared by this process are used to produce polymer composites by combining them with readily available commodity and engineering plastics. The polymer composites are used as coatings, or they are used to fabricate articles, such as free-standing films, fibers, fabrics, foams, molded and laminated articles, tubes, adhesives, and fiber reinforced articles. These articles are well-suited for many applications requiring thermal conductivity, electrical conductivity, antibacterial activity, catalytic activity, and combinations thereof.

Decontamination of metals and polycyclic aromatic hydrocarbons from slag-polluted soil.

PubMed

Bisone, Sara; Mercier, Guy; Blais, Jean-François

2013-01-01

Metallurgy is an industrial activity that is one of the largest contributors to soil contamination by metals. This contamination is often associated with organic compound contamination; however, little research has been aimed at the development of simultaneous processes for decontamination as opposed to treatments to heavy metals or organic compounds alone. This paper presents an efficient process to decontaminate the soils polluted with smelting by-products rich in Cu, Zn and polycyclic aromatic hydrocarbons (PAHs). A simultaneous treatment for metals and PAHs was also tested. The process is mainly based on physical techniques, such as crushing, gravimetric separation and attrition. For the finest particle size fractions, an acid extraction with H2SO4 was used to remove metals. The PAH removal was enhanced by adding surfactant during attrition. The total metal removals varied from 49% to 73% for Cu and from 43% to 63% for Zn, whereas a removal yield of 92% was measured for total PAHs. Finally, a technical-economic evaluation was done for the two processes tested.

Apparatus and method for the electrolytic production of metals

DOEpatents

Sadoway, Donald R.

1991-01-01

Improved electrolytic cells and methods for producing metals by electrolytic reduction of a compound dissolved in a molten electrolyte are disclosed. In the improved cells and methods, a protective surface layer is formed upon at least one electrode in the electrolytic reduction cell and, optionally, upon the lining of the cell. This protective surface layer comprises a material that, at the operating conditions of the cell: (a) is not substantially reduced by the metal product; (b) is not substantially reactive with the cell electrolyte to form materials that are reactive with the metal product; and, (c) has an electrochemical potential that is more electronegative than that of the compound undergoing electrolysis to produce the metal product of the cell. The protective surface layer can be formed upon an electrode metal layer comprising a material, the oxide of which also satisfies the protective layer selection criteria. The protective layer material can also be used on the surface of a cell lining.

Protonation at the aromatic ring of samarium benzophenone dianion species. Isolation and structural characterization of a samarium(III) enolate complex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hou, Z.; Yoshimura, Takashi; Wakatsuki, Yasuo

1994-11-30

The reduction of aromatic compounds into their dihydro derivatives by dissolving metal/alcohol systems (the Birch reduction) is a useful methodology in organic synthesis. Of particular importance is the reduction of aromatic carbonyl compounds such as aromatic acids, esters, amides, and monoaryl ketones, which usually generates in situ useful metal enolate intermediates that upon further reaction with electrophiles yield a variety of cyclohexadiene derivatives. One of the possible processes to generate these metal enolate intermediates is thought to be the monoprotonation of dianionic species at the para position of the aromatic rings. On the other hand, the reduction of diaryl ketonesmore » by alkali metals in liquid ammonia or by lanthanide metals in THF/HMPA or DME has been well known to afford the corresponding ketone dianions. The first X-ray structure of metal ketone dianion complexes, [Yb([mu]-[eta][sup 1],[eta][sup 2]-OCPh[sub 2]) (HMPA)[sub 2

A review of ion and metal pollutants in urban green water infrastructures.

PubMed

Kabir, Md Imran; Daly, Edoardo; Maggi, Federico

2014-02-01

In urban environments, the breakdown of chemicals and pollutants, especially ions and metal compounds, can be favoured by green water infrastructures (GWIs). The overall aim of this review is to set the basis to model GWIs using deterministic approaches in contrast to empirical ones. If a better picture of chemicals and pollutant input and an improved understanding of hydrological and biogeochemical processes affecting these pollutants were known, GWIs could be designed to efficiently retain these pollutants for site-specific meteorological patterns and pollutant load. To this end, we surveyed the existing literature to retrieve a comprehensive dataset of anions and cations, and alkaline and transition metal pollutants incoming to urban environments. Based on this survey, we assessed the pollution load and ecological risk indexes for metals. The existing literature was then surveyed to review the metal retention efficiency of GWIs, and possible biogeochemical processes related to inorganic metal compounds were proposed that could be integrated in biogeochemical models of GWIs. © 2013.

Recent progress in nanocomposites based on conducting polymer: application as electrochemical sensors

NASA Astrophysics Data System (ADS)

El Rhazi, Mama; Majid, Sanaa; Elbasri, Miloud; Salih, Fatima Ezzahra; Oularbi, Larbi; Lafdi, Khalid

2018-06-01

Over the years, intensive research works have been devoted to conducting polymers due to their potential application in many fields such as fuel cell, sensors, and capacitors. To improve the properties of these compounds, several new approaches have been developed which consist in combining conducting polymers and nanoparticles. Then, this review intends to give a clear overview on nanocomposites based on conducting polymers, synthesis, characterization, and their application as electrochemical sensors. For this, the paper is divided into two parts: the first part will highlight the nanocomposites synthesized by combination of carbon nanomaterials (CNMs) and conducting polymers. The preparation of polymer/CNMs such as graphene and carbon nanotube modified electrode is presented coupled with relevant applications. The second part consists of a review of nanocomposites synthesized by combination of metal nanoparticles and conducting polymers.

Theoretical studies of the nitrogen containing compounds adsorption behavior on Na(I)Y and rare earth exchanged RE(III)Y zeolites.

PubMed

Geng, Wei; Zhang, Haitao; Zhao, Xuefei; Zan, Wenyan; Gao, Xionghou; Yao, Xiaojun

2015-01-01

In this work, the adsorption behavior of nitrogen containing compounds including NH3, pyridine, quinoline, and carbazole on Na(I)Y and rare earth exchanged La(III)Y, Pr(III)Y, Nd(III)Y zeolites was investigated by density functional theory (DFT) calculations. The calculation results demonstrate that rare earth exchanged zeolites have stronger adsorption ability for nitrogen containing compounds than Na(I)Y. Rare earth exchanged zeolites exhibit strongest interaction with quinoline while weakest with carbazole. Nd(III)Y zeolites are found to have strongest adsorption to all the studied nitrogen containing compounds. The analysis of the electronic total charge density and electron orbital overlaps show that nitrogen containing compounds interact with zeolites by π-electrons of the compounds and the exchanged metal atom. Mulliken charge population analysis also proves that adsorption energies are strongly dependent on the charge transfer between the nitrogen containing molecules and exchanged metal atom in the zeolites.

Modeling of Heavy Metal Transformation in Soil Ecosystem

NASA Astrophysics Data System (ADS)

Kalinichenko, Kira; Nikovskaya, Galina N.

2017-04-01

The intensification of industrial activity leads to an increase in heavy metals pollution of soils. In our opinion, sludge from biological treatment of municipal waste water, stabilized under aerobic-anaerobic conditions (commonly known as biosolid), may be considered as concentrate of natural soil. In their chemical, physical and chemical and biological properties these systems are similar gel-like nanocomposites. These contain microorganisms, humic substances, clay, clusters of nanoparticles of heavy metal compounds, and so on involved into heteropolysaccharides matrix. It is known that microorganisms play an important role in the transformation of different nature substances in soil and its health maintenance. The regularities of transformation of heavy metal compounds in soil ecosystem were studied at the model of biosolid. At biosolid swelling its structure changing (gel-sol transition, weakening of coagulation contacts between metal containing nanoparticles, microbial cells and metabolites, loosening and even destroying of the nanocomposite structure) can occur [1, 2]. The promotion of the sludge heterotrophic microbial activities leads to solubilization of heavy metal compounds in the system. The microbiological process can be realized in alcaligeneous or acidogeneous regimes in dependence on the type of carbon source and followed by the synthesis of metabolites with the properties of flocculants and heavy metals extragents [3]. In this case the heavy metals solubilization (bioleaching) in the form of nanoparticles of hydroxycarbonate complexes or water soluble complexes with oxycarbonic acids is observed. Under the action of biosolid microorganisms the heavy metals-oxycarbonic acids complexes can be transformed (catabolised) into nano-sizing heavy metals- hydroxycarbonates complexes. These ecologically friendly complexes and microbial heteropolysaccharides are able to interact with soil colloids, stay in the top soil profile, and improve soil structure due to the formation of water-stable aggregates. The alkaligeneous microbiological process in natural ecosystems by co-metabolism of appropriate carbon source is more advantages for environment. Thus the possibility of solubilization of heavy metal compounds in the soil due to stimulating its biological activities of native microorganisms is proved. The studies on the interactions in the system of sludge solid has allowed to develop the "green" biotechnological process of heavy metals solubilization in contaminated soils and sludges. 1. Kalinichenko KV, Nikovskaya GN, and Ulberg ZR (2012) Bioextraction of heavy metals from colloidal sludge systems. Colloid Journ. 74(5) : 553-557. 2. Kalinichenko KV, Nikovskaya GN, and Ulberg ZR (2013) Changes in the surface properties and stability of biocolloids of a sludge system upon extraction of heavy metals. Colloid Journ. 75(3) : 274-278. 3. Nikovskaya GN, Kalinichenko KV (2013) Bioleaching of heavy metals from sludge after biological treatment of municipal effluent. Journ. of Water Chem. and Techn. 35(2) : 80-85.

Transition metal catalyzed manipulation of non-polar carbon–hydrogen bonds for synthetic purpose

PubMed Central

MURAI, Shinji

2011-01-01

The direct addition of ortho C–H bonds in various aromatic compounds such as ketones, esters, imines, imidates, nitriles, and aldehydes to olefins and acetylenes can be achieved with the aid of transition metal catalysts. The ruthenium catalyzed reaction is usually highly efficient and useful as a general synthetic method. The coordination to the metal center by a heteroatom in a directing group such as carbonyl and imino groups in aromatic compounds is the key step in this process. Mechanistically, the reductive elimination to form a C–C bond is the rate-determining step, while the C–H bond cleavage step is not. PMID:21558759